Patrice Wendling

CHICAGO — A second multicenter trial has shown that noninvasive CT angiography is highly accurate in assessing coronary artery disease when compared with conventional invasive angiography.

The per-vessel negative predictive value of 64-slice coronary CT angiography (CCTA) was 97% for identifying blockages greater than 50%, and 99% for blockages greater than 70%, when measured in 232 patients with typical or atypical chest pain in the Assessment by Coronary Computed Tomographic Angiography of Individuals Undergoing Invasive Coronary Angiography (ACCURACY) trial. Positive predictive values were 51% and 33%, respectively, Dr. James K. Min and his associates reported at the annual meeting of the Radiological Society of North America.

“The ACCURACY results [obtained] in a prospective, multicenter fashion definitively establish the high diagnostic accuracy and high negative predictive value of 64-detector-row CT angiography in chest pain patients with intermediate prevalence of coronary artery disease,” said Dr. Min, director of the cardiac CT laboratory at New York-Presbyterian Hospital, New York City.

The findings echo those of the recent Coronary Artery Evaluation Using 64-Row Multidetector Computed Tomography Angiography (CORE-64) trial, in which CT angiography had a 91% positive predictive value and an 83% negative predictive value for identifying significant coronary artery stenoses. CORE-64 was the first large, multicenter trial of the 64-slice technology for coronary angiography, but was criticized by some attendees at the annual scientific sessions of the American Heart Association where it was presented. Concerns were raised that the radiation dose from repeated CT scans could pose a potential cancer risk. No such concerns were raised at the radiology meeting.

To reduce the amount of radiation given to patients in the ACCURACY trial, investigators used a radiation-dose reduction algorithm called EKG modulation that reduces CT angiography radiation by about 40%, Dr. Min said in an interview. The radiation dose per patient was about 10–15 millisieverts (mSv), which is about twice that of an invasive coronary angiogram and about half that of a noninvasive thallium stress test.

Since the trial began, a new algorithm called perspective axial gating has been commercially released and is reported to reduce exposure by 90%, to about 2–4 mSv. Both algorithms work by activating the CT scanner during select parts of the cardiac cycle only, Dr. Min said. For comparison, New York City residents are exposed to about 3 mSv of radiation annually through background exposure.

Neither study used CT angiography for screening. “I believe very emphatically that the data to date don't support CT angiography as a screening tool at all,” Dr. Min said. “In asymptomatic patients, we don't have any data of what to do with the results, and if treatment benefits them.”

CT angiography is of greatest benefit for patients without known coronary disease who have low or intermediate pretest risk. “If you have a high pretest suspicion that someone has coronary artery disease, then direct progression to invasive coronary angiography or even myocardial perfusion imaging is probably a better alternative,” he said.

The ACCURACY trial was unique in that it included all coronary artery segments in its analysis and all patients irrespective of their baseline coronary calcium score. In the CORE-64 trial, stented segments were excluded, as were patients with a calcium score higher than 600. As a result, the ACCURACY findings of high diagnostic accuracy are even more impressive and representative of actual clinical usage, Dr. Min said.

Between May 2006 and January 2007, ACCURACY investigators performed CCTA prior to conventional quantitative coronary angiography (QCA) on 232 patients who had typical or atypical chest pain and had been referred for evaluation at 16 U.S. centers. The images were obtained on a GE Healthcare LightSpeed VCT CT scanner, and analyzed at 15 different locations throughout the coronary tree. The investigators used equipment made by GE Healthcare, which sponsored the study. Dr. Min is on the speakers' bureau for GE Healthcare.

Three independent radiologists interpreted the CCTA images, and one independent radiologist interpreted the QCA images. No segments were excluded based on nonagreement between readers, and only one segment was debated among readers, Dr. Min said.

The patients' mean age was 57 years (range 31–82 years); 138 were male, 203 were white, and 13 were black, and their average body mass index was 31 kg/m

QCA detected 82 blockages greater than 50% in 55 patients and 31 blockages greater than 70% in 34 patients.

For noninvasive CCTA, per-patient sensitivity was 93% and specificity was 82% for blockages greater than 50%; sensitivity was 91% and specificity was 84% for blockages greater than 70%, Dr. Min said.

Additional analyses of the ACCURACY data are being conducted, including a comparison of CT angiography to historical single-photon emission computed tomography (SPECT) imaging, cost-effectiveness versus standard of care, incremental benefit of CT angiography beyond traditional coronary calcium scoring, and interreader, interpatient, and intersegment reliability.

CHICAGO — A second multicenter trial has shown that noninvasive CT angiography is highly accurate in assessing coronary artery disease when compared with conventional invasive angiography.

The per-vessel negative predictive value of 64-slice coronary CT angiography (CCTA) was 97% for identifying blockages greater than 50%, and 99% for blockages greater than 70%, when measured in 232 patients with typical or atypical chest pain in the Assessment by Coronary Computed Tomographic Angiography of Individuals Undergoing Invasive Coronary Angiography (ACCURACY) trial. Positive predictive values were 51% and 33%, respectively, Dr. James K. Min and his associates reported at the annual meeting of the Radiological Society of North America.

“The ACCURACY results [obtained] in a prospective, multicenter fashion definitively establish the high diagnostic accuracy and high negative predictive value of 64-detector-row CT angiography in chest pain patients with intermediate prevalence of coronary artery disease,” said Dr. Min, director of the cardiac CT laboratory at New York-Presbyterian Hospital, New York City.

The findings echo those of the recent Coronary Artery Evaluation Using 64-Row Multidetector Computed Tomography Angiography (CORE-64) trial, in which CT angiography had a 91% positive predictive value and an 83% negative predictive value for identifying significant coronary artery stenoses. CORE-64 was the first large, multicenter trial of the 64-slice technology for coronary angiography, but was criticized by some attendees at the annual scientific sessions of the American Heart Association where it was presented. Concerns were raised that the radiation dose from repeated CT scans could pose a potential cancer risk. No such concerns were raised at the radiology meeting.

To reduce the amount of radiation given to patients in the ACCURACY trial, investigators used a radiation-dose reduction algorithm called EKG modulation that reduces CT angiography radiation by about 40%, Dr. Min said in an interview. The radiation dose per patient was about 10–15 millisieverts (mSv), which is about twice that of an invasive coronary angiogram and about half that of a noninvasive thallium stress test.

Since the trial began, a new algorithm called perspective axial gating has been commercially released and is reported to reduce exposure by 90%, to about 2–4 mSv. Both algorithms work by activating the CT scanner during select parts of the cardiac cycle only, Dr. Min said. For comparison, New York City residents are exposed to about 3 mSv of radiation annually through background exposure.

Neither study used CT angiography for screening. “I believe very emphatically that the data to date don't support CT angiography as a screening tool at all,” Dr. Min said. “In asymptomatic patients, we don't have any data of what to do with the results, and if treatment benefits them.”

CT angiography is of greatest benefit for patients without known coronary disease who have low or intermediate pretest risk. “If you have a high pretest suspicion that someone has coronary artery disease, then direct progression to invasive coronary angiography or even myocardial perfusion imaging is probably a better alternative,” he said.

The ACCURACY trial was unique in that it included all coronary artery segments in its analysis and all patients irrespective of their baseline coronary calcium score. In the CORE-64 trial, stented segments were excluded, as were patients with a calcium score higher than 600. As a result, the ACCURACY findings of high diagnostic accuracy are even more impressive and representative of actual clinical usage, Dr. Min said.

Between May 2006 and January 2007, ACCURACY investigators performed CCTA prior to conventional quantitative coronary angiography (QCA) on 232 patients who had typical or atypical chest pain and had been referred for evaluation at 16 U.S. centers. The images were obtained on a GE Healthcare LightSpeed VCT CT scanner, and analyzed at 15 different locations throughout the coronary tree. The investigators used equipment made by GE Healthcare, which sponsored the study. Dr. Min is on the speakers' bureau for GE Healthcare.

Three independent radiologists interpreted the CCTA images, and one independent radiologist interpreted the QCA images. No segments were excluded based on nonagreement between readers, and only one segment was debated among readers, Dr. Min said.

The patients' mean age was 57 years (range 31–82 years); 138 were male, 203 were white, and 13 were black, and their average body mass index was 31 kg/m

QCA detected 82 blockages greater than 50% in 55 patients and 31 blockages greater than 70% in 34 patients.

For noninvasive CCTA, per-patient sensitivity was 93% and specificity was 82% for blockages greater than 50%; sensitivity was 91% and specificity was 84% for blockages greater than 70%, Dr. Min said.

Additional analyses of the ACCURACY data are being conducted, including a comparison of CT angiography to historical single-photon emission computed tomography (SPECT) imaging, cost-effectiveness versus standard of care, incremental benefit of CT angiography beyond traditional coronary calcium scoring, and interreader, interpatient, and intersegment reliability.

CHICAGO — A second multicenter trial has shown that noninvasive CT angiography is highly accurate in assessing coronary artery disease when compared with conventional invasive angiography.

The per-vessel negative predictive value of 64-slice coronary CT angiography (CCTA) was 97% for identifying blockages greater than 50%, and 99% for blockages greater than 70%, when measured in 232 patients with typical or atypical chest pain in the Assessment by Coronary Computed Tomographic Angiography of Individuals Undergoing Invasive Coronary Angiography (ACCURACY) trial. Positive predictive values were 51% and 33%, respectively, Dr. James K. Min and his associates reported at the annual meeting of the Radiological Society of North America.

“The ACCURACY results [obtained] in a prospective, multicenter fashion definitively establish the high diagnostic accuracy and high negative predictive value of 64-detector-row CT angiography in chest pain patients with intermediate prevalence of coronary artery disease,” said Dr. Min, director of the cardiac CT laboratory at New York-Presbyterian Hospital, New York City.

The findings echo those of the recent Coronary Artery Evaluation Using 64-Row Multidetector Computed Tomography Angiography (CORE-64) trial, in which CT angiography had a 91% positive predictive value and an 83% negative predictive value for identifying significant coronary artery stenoses. CORE-64 was the first large, multicenter trial of the 64-slice technology for coronary angiography, but was criticized by some attendees at the annual scientific sessions of the American Heart Association where it was presented. Concerns were raised that the radiation dose from repeated CT scans could pose a potential cancer risk. No such concerns were raised at the radiology meeting.

To reduce the amount of radiation given to patients in the ACCURACY trial, investigators used a radiation-dose reduction algorithm called EKG modulation that reduces CT angiography radiation by about 40%, Dr. Min said in an interview. The radiation dose per patient was about 10–15 millisieverts (mSv), which is about twice that of an invasive coronary angiogram and about half that of a noninvasive thallium stress test.

Since the trial began, a new algorithm called perspective axial gating has been commercially released and is reported to reduce exposure by 90%, to about 2–4 mSv. Both algorithms work by activating the CT scanner during select parts of the cardiac cycle only, Dr. Min said. For comparison, New York City residents are exposed to about 3 mSv of radiation annually through background exposure.

Neither study used CT angiography for screening. “I believe very emphatically that the data to date don't support CT angiography as a screening tool at all,” Dr. Min said. “In asymptomatic patients, we don't have any data of what to do with the results, and if treatment benefits them.”

CT angiography is of greatest benefit for patients without known coronary disease who have low or intermediate pretest risk. “If you have a high pretest suspicion that someone has coronary artery disease, then direct progression to invasive coronary angiography or even myocardial perfusion imaging is probably a better alternative,” he said.

The ACCURACY trial was unique in that it included all coronary artery segments in its analysis and all patients irrespective of their baseline coronary calcium score. In the CORE-64 trial, stented segments were excluded, as were patients with a calcium score higher than 600. As a result, the ACCURACY findings of high diagnostic accuracy are even more impressive and representative of actual clinical usage, Dr. Min said.

Between May 2006 and January 2007, ACCURACY investigators performed CCTA prior to conventional quantitative coronary angiography (QCA) on 232 patients who had typical or atypical chest pain and had been referred for evaluation at 16 U.S. centers. The images were obtained on a GE Healthcare LightSpeed VCT CT scanner, and analyzed at 15 different locations throughout the coronary tree. The investigators used equipment made by GE Healthcare, which sponsored the study. Dr. Min is on the speakers' bureau for GE Healthcare.

Three independent radiologists interpreted the CCTA images, and one independent radiologist interpreted the QCA images. No segments were excluded based on nonagreement between readers, and only one segment was debated among readers, Dr. Min said.

The patients' mean age was 57 years (range 31–82 years); 138 were male, 203 were white, and 13 were black, and their average body mass index was 31 kg/m

QCA detected 82 blockages greater than 50% in 55 patients and 31 blockages greater than 70% in 34 patients.

For noninvasive CCTA, per-patient sensitivity was 93% and specificity was 82% for blockages greater than 50%; sensitivity was 91% and specificity was 84% for blockages greater than 70%, Dr. Min said.

Additional analyses of the ACCURACY data are being conducted, including a comparison of CT angiography to historical single-photon emission computed tomography (SPECT) imaging, cost-effectiveness versus standard of care, incremental benefit of CT angiography beyond traditional coronary calcium scoring, and interreader, interpatient, and intersegment reliability.

CHICAGO — The Pulmonary Embolism Severity Index provides clinicians with a useful tool for selecting patients with acute pulmonary embolism for outpatient therapy, Col. Lisa K. Moores, MC, USA, said.

Recent evidence suggests that many patients presenting in the emergency department with nonmassive pulmonary embolism (PE) can be safely treated as outpatients using low-molecular-weight heparins, or discharged early. Based on this growing body of evidence, the British Thoracic Society now recommends outpatient treatment for clinically stable patients with PE.

The Pulmonary Embolism Severity Index (PESI) and Geneva score are two standardized prognostic models that have been recently developed to identify patients at low risk for PE. The PESI uses 11 clinical findings routinely available at presentation that were previously shown to be associated with mortality in patients with PE or other acute diseases, said Dr. Moores, assistant dean for clinical sciences at the Uniformed Services University of the Health Sciences, Bethesda, Md.

These variables include demographics (age and male sex); comorbid conditions (cancer, chronic heart failure, and chronic lung disease); and six signs, including a heart rate of 110 bpm or more; systolic blood pressure less than 100 mm Hg; respiratory rate of 30 bpm or more; temperature less than 36° C; altered mental state; and oxygen saturation less than 90%.

A score is calculated by using age, then adding points based on the various factors present. Patients are then stratified by their score into five severity classes of increasing risk of death and other adverse outcomes.

A validation study demonstrated that patients in PESI class I (no more than 65 points) and class II (66–85 points) had a 30-day mortality of 1.6% or less and 3.5% or less, respectively (Am. J. Respir. Crit. Care Med. 2005;172:1041–6). Nonfatal cardiogenic shock or cardiorespiratory arrest occurred in 1% or less in class I and 1.3% or less in class II, and no patient in these two classes had nonfatal bleeding or recurrent venous thromboembolism, Dr. Moores said at the annual meeting of the American College of Chest Physicians (ACCP).

The Geneva score has been validated in two studies and uses six factors to stratify patients as low risk (up to 2 points) or high risk (3 points or more). Those factors are cancer, heart failure, previous deep vein thrombosis, systolic BP less than 100 mm Hg, arterial oxygen pressure less than 60 mm Hg, and deep vein thrombosis on ultrasound. Of 180 low-risk patients, only 4 (2%) had an adverse outcome, compared with 23 of 88 (26%) high-risk patients (Thromb. Haemost. 2000;84:548–52).

Dr. Moores acknowledged that the PESI model is “harder to get your hands around” than the Geneva model, but said some of the most intriguing data of 2007 suggest that the PESI is “more accurate and clinically useful.” An independent, head-to-head comparison in which the models were retrospectively applied to a cohort of 599 patients with objectively confirmed PE indicated a 30-day mortality in Geneva low-risk patients of 5.6%, compared with a mortality in PESI low-risk (class I and class II) patients of 0.9% (Chest 2007;132:24–30). The PESI classified significantly fewer patients as low risk than did the Geneva model (36% vs. 84%), but the area under the receiver operating characteristic curve was higher for the PESI (0.76 vs. 0.61).

“More patients can be classified via Geneva as low risk, but the difference in mortality rates between the two systems suggests doing it more safely with the PESI,” Dr. Moores said.

Dr. Moores suggests that patients with a higher PESI class (class III-IV) should be observed in the ICU or a telemetry unit for the first 24 hours. In addition, clinicians should consider evaluating biomarkers in these patients such as troponin, brain natriuretic peptide, and N-terminal pro-brain natriuretic peptide levels, which when elevated have been correlated with PE death.

An audience member asked if the PESI or Geneva models can be used to select patients for thrombolysis, but Dr. Moores said the predictive values drop off in higher-risk patients. “Where the crossover point is to say a patient needs thrombolysis is not yet available,” she said.

Dr. Moores said in an interview that she was unaware of an American Thoracic Society recommendation for outpatient therapy for patients with PE, and that the new ACCP guidelines mention potential outpatient therapy, but do not review the PESI or make a recommendation about outpatient therapy.

CHICAGO — The Pulmonary Embolism Severity Index provides clinicians with a useful tool for selecting patients with acute pulmonary embolism for outpatient therapy, Col. Lisa K. Moores, MC, USA, said.

Recent evidence suggests that many patients presenting in the emergency department with nonmassive pulmonary embolism (PE) can be safely treated as outpatients using low-molecular-weight heparins, or discharged early. Based on this growing body of evidence, the British Thoracic Society now recommends outpatient treatment for clinically stable patients with PE.

The Pulmonary Embolism Severity Index (PESI) and Geneva score are two standardized prognostic models that have been recently developed to identify patients at low risk for PE. The PESI uses 11 clinical findings routinely available at presentation that were previously shown to be associated with mortality in patients with PE or other acute diseases, said Dr. Moores, assistant dean for clinical sciences at the Uniformed Services University of the Health Sciences, Bethesda, Md.

These variables include demographics (age and male sex); comorbid conditions (cancer, chronic heart failure, and chronic lung disease); and six signs, including a heart rate of 110 bpm or more; systolic blood pressure less than 100 mm Hg; respiratory rate of 30 bpm or more; temperature less than 36° C; altered mental state; and oxygen saturation less than 90%.

A score is calculated by using age, then adding points based on the various factors present. Patients are then stratified by their score into five severity classes of increasing risk of death and other adverse outcomes.

A validation study demonstrated that patients in PESI class I (no more than 65 points) and class II (66–85 points) had a 30-day mortality of 1.6% or less and 3.5% or less, respectively (Am. J. Respir. Crit. Care Med. 2005;172:1041–6). Nonfatal cardiogenic shock or cardiorespiratory arrest occurred in 1% or less in class I and 1.3% or less in class II, and no patient in these two classes had nonfatal bleeding or recurrent venous thromboembolism, Dr. Moores said at the annual meeting of the American College of Chest Physicians (ACCP).

The Geneva score has been validated in two studies and uses six factors to stratify patients as low risk (up to 2 points) or high risk (3 points or more). Those factors are cancer, heart failure, previous deep vein thrombosis, systolic BP less than 100 mm Hg, arterial oxygen pressure less than 60 mm Hg, and deep vein thrombosis on ultrasound. Of 180 low-risk patients, only 4 (2%) had an adverse outcome, compared with 23 of 88 (26%) high-risk patients (Thromb. Haemost. 2000;84:548–52).

Dr. Moores acknowledged that the PESI model is “harder to get your hands around” than the Geneva model, but said some of the most intriguing data of 2007 suggest that the PESI is “more accurate and clinically useful.” An independent, head-to-head comparison in which the models were retrospectively applied to a cohort of 599 patients with objectively confirmed PE indicated a 30-day mortality in Geneva low-risk patients of 5.6%, compared with a mortality in PESI low-risk (class I and class II) patients of 0.9% (Chest 2007;132:24–30). The PESI classified significantly fewer patients as low risk than did the Geneva model (36% vs. 84%), but the area under the receiver operating characteristic curve was higher for the PESI (0.76 vs. 0.61).

“More patients can be classified via Geneva as low risk, but the difference in mortality rates between the two systems suggests doing it more safely with the PESI,” Dr. Moores said.

Dr. Moores suggests that patients with a higher PESI class (class III-IV) should be observed in the ICU or a telemetry unit for the first 24 hours. In addition, clinicians should consider evaluating biomarkers in these patients such as troponin, brain natriuretic peptide, and N-terminal pro-brain natriuretic peptide levels, which when elevated have been correlated with PE death.

An audience member asked if the PESI or Geneva models can be used to select patients for thrombolysis, but Dr. Moores said the predictive values drop off in higher-risk patients. “Where the crossover point is to say a patient needs thrombolysis is not yet available,” she said.

Dr. Moores said in an interview that she was unaware of an American Thoracic Society recommendation for outpatient therapy for patients with PE, and that the new ACCP guidelines mention potential outpatient therapy, but do not review the PESI or make a recommendation about outpatient therapy.

CHICAGO — The Pulmonary Embolism Severity Index provides clinicians with a useful tool for selecting patients with acute pulmonary embolism for outpatient therapy, Col. Lisa K. Moores, MC, USA, said.

Recent evidence suggests that many patients presenting in the emergency department with nonmassive pulmonary embolism (PE) can be safely treated as outpatients using low-molecular-weight heparins, or discharged early. Based on this growing body of evidence, the British Thoracic Society now recommends outpatient treatment for clinically stable patients with PE.

The Pulmonary Embolism Severity Index (PESI) and Geneva score are two standardized prognostic models that have been recently developed to identify patients at low risk for PE. The PESI uses 11 clinical findings routinely available at presentation that were previously shown to be associated with mortality in patients with PE or other acute diseases, said Dr. Moores, assistant dean for clinical sciences at the Uniformed Services University of the Health Sciences, Bethesda, Md.

These variables include demographics (age and male sex); comorbid conditions (cancer, chronic heart failure, and chronic lung disease); and six signs, including a heart rate of 110 bpm or more; systolic blood pressure less than 100 mm Hg; respiratory rate of 30 bpm or more; temperature less than 36° C; altered mental state; and oxygen saturation less than 90%.

A score is calculated by using age, then adding points based on the various factors present. Patients are then stratified by their score into five severity classes of increasing risk of death and other adverse outcomes.

A validation study demonstrated that patients in PESI class I (no more than 65 points) and class II (66–85 points) had a 30-day mortality of 1.6% or less and 3.5% or less, respectively (Am. J. Respir. Crit. Care Med. 2005;172:1041–6). Nonfatal cardiogenic shock or cardiorespiratory arrest occurred in 1% or less in class I and 1.3% or less in class II, and no patient in these two classes had nonfatal bleeding or recurrent venous thromboembolism, Dr. Moores said at the annual meeting of the American College of Chest Physicians (ACCP).

The Geneva score has been validated in two studies and uses six factors to stratify patients as low risk (up to 2 points) or high risk (3 points or more). Those factors are cancer, heart failure, previous deep vein thrombosis, systolic BP less than 100 mm Hg, arterial oxygen pressure less than 60 mm Hg, and deep vein thrombosis on ultrasound. Of 180 low-risk patients, only 4 (2%) had an adverse outcome, compared with 23 of 88 (26%) high-risk patients (Thromb. Haemost. 2000;84:548–52).

Dr. Moores acknowledged that the PESI model is “harder to get your hands around” than the Geneva model, but said some of the most intriguing data of 2007 suggest that the PESI is “more accurate and clinically useful.” An independent, head-to-head comparison in which the models were retrospectively applied to a cohort of 599 patients with objectively confirmed PE indicated a 30-day mortality in Geneva low-risk patients of 5.6%, compared with a mortality in PESI low-risk (class I and class II) patients of 0.9% (Chest 2007;132:24–30). The PESI classified significantly fewer patients as low risk than did the Geneva model (36% vs. 84%), but the area under the receiver operating characteristic curve was higher for the PESI (0.76 vs. 0.61).

“More patients can be classified via Geneva as low risk, but the difference in mortality rates between the two systems suggests doing it more safely with the PESI,” Dr. Moores said.

Dr. Moores suggests that patients with a higher PESI class (class III-IV) should be observed in the ICU or a telemetry unit for the first 24 hours. In addition, clinicians should consider evaluating biomarkers in these patients such as troponin, brain natriuretic peptide, and N-terminal pro-brain natriuretic peptide levels, which when elevated have been correlated with PE death.

An audience member asked if the PESI or Geneva models can be used to select patients for thrombolysis, but Dr. Moores said the predictive values drop off in higher-risk patients. “Where the crossover point is to say a patient needs thrombolysis is not yet available,” she said.

Dr. Moores said in an interview that she was unaware of an American Thoracic Society recommendation for outpatient therapy for patients with PE, and that the new ACCP guidelines mention potential outpatient therapy, but do not review the PESI or make a recommendation about outpatient therapy.

CHICAGO — A simple severity-assessment tool for community-acquired pneumonia accurately identified patients needing intensive respiratory or inotropic support in a 7,464-patient, multicenter validation study.

SMART-COP was developed as part of the Australian Community-Acquired Pneumonia (CAP) study and measures eight features readily available at the time of initial assessment: low systolic blood pressure (less than 90 mm Hg), multilobar chest x-ray involvement, low albumin level (less than 3.5 g/dL), high respiratory rate (age-adjusted cutoffs), tachycardia (at least 125 beats per minute), confusion (new onset), poor oxygenation (age-adjusted cutoffs), and low arterial pH (less than 7.35).

A modified version for primary care physicians, called SMRT-CO, does not require the results of investigations such as serum albumin, arterial pH, and arterial oxygen tension.

For SMART-COP and SMRT-CO, the cutoff scores for increased risk of needing intensive respiratory or inotropic support (IRIS) are at least three points and at least two points, respectively, Dr. Patrick G.P. Charles of the department of infectious diseases, Austin Health, Heidelberg, Australia, and his associates reported in a late-breaking poster at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.

The investigators calculated the area under the receiver operating characteristic (ROC) curve and the Hosemer-Lemeshow goodness-of-fit statistic to determine the ability of SMART-COP to predict the need for IRIS among 7,464 patients from five CAP databases, including 474 patients who needed IRIS. The patients' mean age was 65 years (range 18–100 years).

Sensitivity and specificity for SMART-COP in each of the five databases were 80% and 61%, 58% and 75.5%, 69% and 73%, 86% and 73%, and 89% and 46%, respectively. For SMRT-CO, those results were 86% and 51%, 71% and 59%, 81% and 58%, 85% and 55%, and 95% and 36%, respectively. This high accuracy was found even though it wasn't possible in most cases to assess the lower cutoff values for respiratory rate and oxygenation in patients aged 50 years or younger, the investigators reported at the meeting sponsored by the American Society for Microbiology.

Some databases didn't record actual values, but simply noted whether, for example, the respiratory rate was 30 breaths or more per minute. In the SMART-COP model, the cutoff is at least 25 breaths per minute for patients aged 50 years or less, and at least 30 breaths per minute for those older than 50.

Without the actual value for each test, the missing data were assumed to be normal, and no points could be assigned, Dr. Charles explained in an interview. He said it is difficult to know exactly how many data points were missing, but noted that albumin level and arterial blood gases were not recorded in about 4,500 patients.

“Based on this, it is very likely that the SMART-COP scores given to many patients were inappropriately low, making the sensitivity figures look lower than they probably should be if complete data were available,” Dr. Charles said. “A prospective study is planned, which should answer this.”

CHICAGO — A simple severity-assessment tool for community-acquired pneumonia accurately identified patients needing intensive respiratory or inotropic support in a 7,464-patient, multicenter validation study.

SMART-COP was developed as part of the Australian Community-Acquired Pneumonia (CAP) study and measures eight features readily available at the time of initial assessment: low systolic blood pressure (less than 90 mm Hg), multilobar chest x-ray involvement, low albumin level (less than 3.5 g/dL), high respiratory rate (age-adjusted cutoffs), tachycardia (at least 125 beats per minute), confusion (new onset), poor oxygenation (age-adjusted cutoffs), and low arterial pH (less than 7.35).

A modified version for primary care physicians, called SMRT-CO, does not require the results of investigations such as serum albumin, arterial pH, and arterial oxygen tension.

For SMART-COP and SMRT-CO, the cutoff scores for increased risk of needing intensive respiratory or inotropic support (IRIS) are at least three points and at least two points, respectively, Dr. Patrick G.P. Charles of the department of infectious diseases, Austin Health, Heidelberg, Australia, and his associates reported in a late-breaking poster at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.

The investigators calculated the area under the receiver operating characteristic (ROC) curve and the Hosemer-Lemeshow goodness-of-fit statistic to determine the ability of SMART-COP to predict the need for IRIS among 7,464 patients from five CAP databases, including 474 patients who needed IRIS. The patients' mean age was 65 years (range 18–100 years).

Sensitivity and specificity for SMART-COP in each of the five databases were 80% and 61%, 58% and 75.5%, 69% and 73%, 86% and 73%, and 89% and 46%, respectively. For SMRT-CO, those results were 86% and 51%, 71% and 59%, 81% and 58%, 85% and 55%, and 95% and 36%, respectively. This high accuracy was found even though it wasn't possible in most cases to assess the lower cutoff values for respiratory rate and oxygenation in patients aged 50 years or younger, the investigators reported at the meeting sponsored by the American Society for Microbiology.

Some databases didn't record actual values, but simply noted whether, for example, the respiratory rate was 30 breaths or more per minute. In the SMART-COP model, the cutoff is at least 25 breaths per minute for patients aged 50 years or less, and at least 30 breaths per minute for those older than 50.

Without the actual value for each test, the missing data were assumed to be normal, and no points could be assigned, Dr. Charles explained in an interview. He said it is difficult to know exactly how many data points were missing, but noted that albumin level and arterial blood gases were not recorded in about 4,500 patients.

“Based on this, it is very likely that the SMART-COP scores given to many patients were inappropriately low, making the sensitivity figures look lower than they probably should be if complete data were available,” Dr. Charles said. “A prospective study is planned, which should answer this.”

CHICAGO — A simple severity-assessment tool for community-acquired pneumonia accurately identified patients needing intensive respiratory or inotropic support in a 7,464-patient, multicenter validation study.

SMART-COP was developed as part of the Australian Community-Acquired Pneumonia (CAP) study and measures eight features readily available at the time of initial assessment: low systolic blood pressure (less than 90 mm Hg), multilobar chest x-ray involvement, low albumin level (less than 3.5 g/dL), high respiratory rate (age-adjusted cutoffs), tachycardia (at least 125 beats per minute), confusion (new onset), poor oxygenation (age-adjusted cutoffs), and low arterial pH (less than 7.35).

A modified version for primary care physicians, called SMRT-CO, does not require the results of investigations such as serum albumin, arterial pH, and arterial oxygen tension.

For SMART-COP and SMRT-CO, the cutoff scores for increased risk of needing intensive respiratory or inotropic support (IRIS) are at least three points and at least two points, respectively, Dr. Patrick G.P. Charles of the department of infectious diseases, Austin Health, Heidelberg, Australia, and his associates reported in a late-breaking poster at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.

The investigators calculated the area under the receiver operating characteristic (ROC) curve and the Hosemer-Lemeshow goodness-of-fit statistic to determine the ability of SMART-COP to predict the need for IRIS among 7,464 patients from five CAP databases, including 474 patients who needed IRIS. The patients' mean age was 65 years (range 18–100 years).

Sensitivity and specificity for SMART-COP in each of the five databases were 80% and 61%, 58% and 75.5%, 69% and 73%, 86% and 73%, and 89% and 46%, respectively. For SMRT-CO, those results were 86% and 51%, 71% and 59%, 81% and 58%, 85% and 55%, and 95% and 36%, respectively. This high accuracy was found even though it wasn't possible in most cases to assess the lower cutoff values for respiratory rate and oxygenation in patients aged 50 years or younger, the investigators reported at the meeting sponsored by the American Society for Microbiology.

Some databases didn't record actual values, but simply noted whether, for example, the respiratory rate was 30 breaths or more per minute. In the SMART-COP model, the cutoff is at least 25 breaths per minute for patients aged 50 years or less, and at least 30 breaths per minute for those older than 50.

Without the actual value for each test, the missing data were assumed to be normal, and no points could be assigned, Dr. Charles explained in an interview. He said it is difficult to know exactly how many data points were missing, but noted that albumin level and arterial blood gases were not recorded in about 4,500 patients.

“Based on this, it is very likely that the SMART-COP scores given to many patients were inappropriately low, making the sensitivity figures look lower than they probably should be if complete data were available,” Dr. Charles said. “A prospective study is planned, which should answer this.”

CHICAGO — Primary care physicians are willing to assume a greater role in providing comprehensive care to adult cancer survivors, new data suggest.

Of 330 community-based primary care physicians surveyed in Canada, 40% said they would be willing to assume exclusive care of patients immediately or within 1 year after completion of active treatment for breast, prostate, and colorectal cancer. One-third of physicians in the cross-sectional survey said they would do so for lymphoma patients.

Physicians located farther from cancer specialists were willing to accept earlier exclusive care of breast, prostate, and colorectal cancer survivors, but not lymphoma survivors. For all four cancer sites, physicians already providing care were significantly more likely to provide earlier exclusive care, according to results presented in a poster at the annual meeting of the American Society of Clinical Oncology.

The majority of physicians (69%) worked in a group practice, with 42% practicing in cities, 21% in suburbs, and 37% in rural areas or small towns. The average time to the closest cancer center was 58 minutes (median 30 minutes).

Follow-up care was defined as "well" routine cancer follow-up, and care after active treatment including surgery, chemotherapy, or radiation was complete and presumably curative.

Some Canadian oncology programs are starting to move toward discharging patients who are expected to do well or who are long-time survivors, lead investigator Dr. Lisa Del Giudice said in an interview.

Shifting care back to primary care physicians would make more efficient use of specialist care resources. However, more information was needed about the attitudes of primary care physicians and their willingness to provide exclusive care. There are national and cancer organization guidelines regarding when to perform specific tests, but those guidelines don't address who should provide follow-up care, said Dr. Del Guidice of the University of Toronto and the Sunnybrook Health Sciences Centre.

Primary care physicians reported that the most useful tool in assuming patient care would be a standardized letter from oncologists that addresses the individual patient's needs. This was followed by printed guidelines, expedited re-referral to specialists, and telephone or mail advice from the specialist. More medical or support staff and pamphlets ranked at the bottom of the list.

Most respondents selected share care as their preferred model of routine care, and two-thirds of physicians reported they should be involved at an earlier stage in follow-up.

Primary care physicians were confident in their abilities, with two-thirds reporting they have the skills necessary to provide routine follow-up care. Just 37% agreed that specialists were more efficient at detecting occurrences than primary care physicians. More than half (55%) of respondents reported that specialist clinics were overcrowded.

A majority (80%) of physicians felt they were more appropriate providers than specialists for addressing psychosocial support issues, Dr. Del Giudice and associates reported.

Although having primary care physicians provide follow-up cancer care could be cost effective, there are obstacles. Among respondents, 72% felt patients expect cancer follow-up from specialists, and only 23% believed that patients would rather go to their primary care physician for that care. And 40% believed patients would not be adequately assured with follow-up from their primary care physician.

A randomized trial is planned to evaluate patient acceptance, and a second trial will examine administrative data to determine current practices and trends in follow-up cancer care in Canada, Dr. Del Giudice said.

CHICAGO — Primary care physicians are willing to assume a greater role in providing comprehensive care to adult cancer survivors, new data suggest.

Of 330 community-based primary care physicians surveyed in Canada, 40% said they would be willing to assume exclusive care of patients immediately or within 1 year after completion of active treatment for breast, prostate, and colorectal cancer. One-third of physicians in the cross-sectional survey said they would do so for lymphoma patients.

Physicians located farther from cancer specialists were willing to accept earlier exclusive care of breast, prostate, and colorectal cancer survivors, but not lymphoma survivors. For all four cancer sites, physicians already providing care were significantly more likely to provide earlier exclusive care, according to results presented in a poster at the annual meeting of the American Society of Clinical Oncology.

The majority of physicians (69%) worked in a group practice, with 42% practicing in cities, 21% in suburbs, and 37% in rural areas or small towns. The average time to the closest cancer center was 58 minutes (median 30 minutes).

Follow-up care was defined as "well" routine cancer follow-up, and care after active treatment including surgery, chemotherapy, or radiation was complete and presumably curative.

Some Canadian oncology programs are starting to move toward discharging patients who are expected to do well or who are long-time survivors, lead investigator Dr. Lisa Del Giudice said in an interview.

Shifting care back to primary care physicians would make more efficient use of specialist care resources. However, more information was needed about the attitudes of primary care physicians and their willingness to provide exclusive care. There are national and cancer organization guidelines regarding when to perform specific tests, but those guidelines don't address who should provide follow-up care, said Dr. Del Guidice of the University of Toronto and the Sunnybrook Health Sciences Centre.

Primary care physicians reported that the most useful tool in assuming patient care would be a standardized letter from oncologists that addresses the individual patient's needs. This was followed by printed guidelines, expedited re-referral to specialists, and telephone or mail advice from the specialist. More medical or support staff and pamphlets ranked at the bottom of the list.

Most respondents selected share care as their preferred model of routine care, and two-thirds of physicians reported they should be involved at an earlier stage in follow-up.

Primary care physicians were confident in their abilities, with two-thirds reporting they have the skills necessary to provide routine follow-up care. Just 37% agreed that specialists were more efficient at detecting occurrences than primary care physicians. More than half (55%) of respondents reported that specialist clinics were overcrowded.

A majority (80%) of physicians felt they were more appropriate providers than specialists for addressing psychosocial support issues, Dr. Del Giudice and associates reported.

Although having primary care physicians provide follow-up cancer care could be cost effective, there are obstacles. Among respondents, 72% felt patients expect cancer follow-up from specialists, and only 23% believed that patients would rather go to their primary care physician for that care. And 40% believed patients would not be adequately assured with follow-up from their primary care physician.

A randomized trial is planned to evaluate patient acceptance, and a second trial will examine administrative data to determine current practices and trends in follow-up cancer care in Canada, Dr. Del Giudice said.

CHICAGO — Primary care physicians are willing to assume a greater role in providing comprehensive care to adult cancer survivors, new data suggest.

Of 330 community-based primary care physicians surveyed in Canada, 40% said they would be willing to assume exclusive care of patients immediately or within 1 year after completion of active treatment for breast, prostate, and colorectal cancer. One-third of physicians in the cross-sectional survey said they would do so for lymphoma patients.

Physicians located farther from cancer specialists were willing to accept earlier exclusive care of breast, prostate, and colorectal cancer survivors, but not lymphoma survivors. For all four cancer sites, physicians already providing care were significantly more likely to provide earlier exclusive care, according to results presented in a poster at the annual meeting of the American Society of Clinical Oncology.

The majority of physicians (69%) worked in a group practice, with 42% practicing in cities, 21% in suburbs, and 37% in rural areas or small towns. The average time to the closest cancer center was 58 minutes (median 30 minutes).

Follow-up care was defined as "well" routine cancer follow-up, and care after active treatment including surgery, chemotherapy, or radiation was complete and presumably curative.

Some Canadian oncology programs are starting to move toward discharging patients who are expected to do well or who are long-time survivors, lead investigator Dr. Lisa Del Giudice said in an interview.

Shifting care back to primary care physicians would make more efficient use of specialist care resources. However, more information was needed about the attitudes of primary care physicians and their willingness to provide exclusive care. There are national and cancer organization guidelines regarding when to perform specific tests, but those guidelines don't address who should provide follow-up care, said Dr. Del Guidice of the University of Toronto and the Sunnybrook Health Sciences Centre.

Primary care physicians reported that the most useful tool in assuming patient care would be a standardized letter from oncologists that addresses the individual patient's needs. This was followed by printed guidelines, expedited re-referral to specialists, and telephone or mail advice from the specialist. More medical or support staff and pamphlets ranked at the bottom of the list.

Most respondents selected share care as their preferred model of routine care, and two-thirds of physicians reported they should be involved at an earlier stage in follow-up.

Primary care physicians were confident in their abilities, with two-thirds reporting they have the skills necessary to provide routine follow-up care. Just 37% agreed that specialists were more efficient at detecting occurrences than primary care physicians. More than half (55%) of respondents reported that specialist clinics were overcrowded.

A majority (80%) of physicians felt they were more appropriate providers than specialists for addressing psychosocial support issues, Dr. Del Giudice and associates reported.

Although having primary care physicians provide follow-up cancer care could be cost effective, there are obstacles. Among respondents, 72% felt patients expect cancer follow-up from specialists, and only 23% believed that patients would rather go to their primary care physician for that care. And 40% believed patients would not be adequately assured with follow-up from their primary care physician.

A randomized trial is planned to evaluate patient acceptance, and a second trial will examine administrative data to determine current practices and trends in follow-up cancer care in Canada, Dr. Del Giudice said.

CHICAGO — The pUSA03 subclone of the USA300 strain is emerging as a major cause of community-acquired methicillin-resistant Staphylococcus aureus, especially in men who have sex with men.

The new strain is likely spread through skin-to-skin, sexual contact, Dr. Binh An Diep, Ph.D., and associates reported in a poster at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.

USA300 has recently emerged as the predominant cause of community-acquired MRSA and skin and soft-tissue infections in the United States.

A population-based study that involved all MRSA infections treated at 9 of 10 participating medical centers in San Francisco shows the incidence of the pUSA03 subclone was 171 cases per 100,000 in one San Francisco ZIP code. That compares with 57 cases per 100,000 in three other city ZIP codes and 47 cases per 100,000 in four other city ZIP codes.

The high-incidence ZIP code (94114) corresponds to the Castro district, which has the highest concentration of gay men in the United States.

The Castro neighborhood is an affluent area with an average annual income of $90,000, making it less likely that the majority of infected individuals were IV drug users, Dr. Diep, of the University of California, San Francisco, said in an interview.

"The mechanism seems to be one of skin-to-skin contact, and having very vigorous perianal sex that creates a breach of the skin barrier leading to perianal abscess," he said.

A previous report in six heterosexual patients supports this largely unrecognized method of transmission for community-acquired MRSA (Clin. Infect. Dis. 2007;44:410-13).

"The take-home message is really personal hygiene," Dr. Diep said.

"Because MRSA is now spread skin-to-skin, wearing a condom won't help. So you have to be very careful and bathe yourself very well."

The investigators also reviewed the medical charts of 183 patients treated at San Francisco General's Hospital Positive Health Program, an outpatient HIV clinic, and the charts of 130 patients treated at Boston's Fenway Community Health, which also has an outpatient clinic.

MRSA isolates, cultured predominantly from skin and soft-tissue infection sites, were genotyped, and pUSA03 was detected using polymerase chain reaction assays.

Investigators detected the pUSA03 subclone in about 29% of patients from both surveys, and, of these, 99% were men who have sex with men. Among homosexual men who were infected with the pUSA03 subclone of USA300, 39% (35 of 89) had infections that involved the buttocks and genitoperineal area, and 30% (27 of 89) had infections that involved the extremities.

In the San Francisco survey, being a man who has sex with men was the strongest predictor of infection with the pUSA03 subclone after controlling for the effects of a previous MRSA infection and for clindamycin use in the previous year.

Previous use of trimethoprim-sulfamethoxazole was significantly associated with pUSA03 subclone infection, but prior use of mupirocin and hospitalization in the previous year were not significant risk factors, the investigators reported at the meeting, which was sponsored by the American Society for Microbiology.

In the Boston cohort, multidrug-resistant USA300 carrying the pUSA03 plasmid was recovered exclusively among men having sex with men.

The percentage of USA300 resistant to multiple classes of commonly used antimicrobial agents, including beta-lactams, macrolides, clindamycin, tetracyclines, and mupirocin, varied in the surveys from location to location.

In San Francisco, 18% of USA300 isolates were multidrug-resistant, whereas in Boston, 48% of the isolates were multidrug-resistant, Dr. Diep said.

CHICAGO — The pUSA03 subclone of the USA300 strain is emerging as a major cause of community-acquired methicillin-resistant Staphylococcus aureus, especially in men who have sex with men.

The new strain is likely spread through skin-to-skin, sexual contact, Dr. Binh An Diep, Ph.D., and associates reported in a poster at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.

USA300 has recently emerged as the predominant cause of community-acquired MRSA and skin and soft-tissue infections in the United States.

A population-based study that involved all MRSA infections treated at 9 of 10 participating medical centers in San Francisco shows the incidence of the pUSA03 subclone was 171 cases per 100,000 in one San Francisco ZIP code. That compares with 57 cases per 100,000 in three other city ZIP codes and 47 cases per 100,000 in four other city ZIP codes.

The high-incidence ZIP code (94114) corresponds to the Castro district, which has the highest concentration of gay men in the United States.

The Castro neighborhood is an affluent area with an average annual income of $90,000, making it less likely that the majority of infected individuals were IV drug users, Dr. Diep, of the University of California, San Francisco, said in an interview.

"The mechanism seems to be one of skin-to-skin contact, and having very vigorous perianal sex that creates a breach of the skin barrier leading to perianal abscess," he said.

A previous report in six heterosexual patients supports this largely unrecognized method of transmission for community-acquired MRSA (Clin. Infect. Dis. 2007;44:410-13).

"The take-home message is really personal hygiene," Dr. Diep said.

"Because MRSA is now spread skin-to-skin, wearing a condom won't help. So you have to be very careful and bathe yourself very well."

The investigators also reviewed the medical charts of 183 patients treated at San Francisco General's Hospital Positive Health Program, an outpatient HIV clinic, and the charts of 130 patients treated at Boston's Fenway Community Health, which also has an outpatient clinic.

MRSA isolates, cultured predominantly from skin and soft-tissue infection sites, were genotyped, and pUSA03 was detected using polymerase chain reaction assays.

Investigators detected the pUSA03 subclone in about 29% of patients from both surveys, and, of these, 99% were men who have sex with men. Among homosexual men who were infected with the pUSA03 subclone of USA300, 39% (35 of 89) had infections that involved the buttocks and genitoperineal area, and 30% (27 of 89) had infections that involved the extremities.

In the San Francisco survey, being a man who has sex with men was the strongest predictor of infection with the pUSA03 subclone after controlling for the effects of a previous MRSA infection and for clindamycin use in the previous year.

Previous use of trimethoprim-sulfamethoxazole was significantly associated with pUSA03 subclone infection, but prior use of mupirocin and hospitalization in the previous year were not significant risk factors, the investigators reported at the meeting, which was sponsored by the American Society for Microbiology.

In the Boston cohort, multidrug-resistant USA300 carrying the pUSA03 plasmid was recovered exclusively among men having sex with men.

The percentage of USA300 resistant to multiple classes of commonly used antimicrobial agents, including beta-lactams, macrolides, clindamycin, tetracyclines, and mupirocin, varied in the surveys from location to location.

In San Francisco, 18% of USA300 isolates were multidrug-resistant, whereas in Boston, 48% of the isolates were multidrug-resistant, Dr. Diep said.

CHICAGO — The pUSA03 subclone of the USA300 strain is emerging as a major cause of community-acquired methicillin-resistant Staphylococcus aureus, especially in men who have sex with men.

The new strain is likely spread through skin-to-skin, sexual contact, Dr. Binh An Diep, Ph.D., and associates reported in a poster at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.

USA300 has recently emerged as the predominant cause of community-acquired MRSA and skin and soft-tissue infections in the United States.

A population-based study that involved all MRSA infections treated at 9 of 10 participating medical centers in San Francisco shows the incidence of the pUSA03 subclone was 171 cases per 100,000 in one San Francisco ZIP code. That compares with 57 cases per 100,000 in three other city ZIP codes and 47 cases per 100,000 in four other city ZIP codes.

The high-incidence ZIP code (94114) corresponds to the Castro district, which has the highest concentration of gay men in the United States.

The Castro neighborhood is an affluent area with an average annual income of $90,000, making it less likely that the majority of infected individuals were IV drug users, Dr. Diep, of the University of California, San Francisco, said in an interview.

"The mechanism seems to be one of skin-to-skin contact, and having very vigorous perianal sex that creates a breach of the skin barrier leading to perianal abscess," he said.

A previous report in six heterosexual patients supports this largely unrecognized method of transmission for community-acquired MRSA (Clin. Infect. Dis. 2007;44:410-13).

"The take-home message is really personal hygiene," Dr. Diep said.

"Because MRSA is now spread skin-to-skin, wearing a condom won't help. So you have to be very careful and bathe yourself very well."

The investigators also reviewed the medical charts of 183 patients treated at San Francisco General's Hospital Positive Health Program, an outpatient HIV clinic, and the charts of 130 patients treated at Boston's Fenway Community Health, which also has an outpatient clinic.

MRSA isolates, cultured predominantly from skin and soft-tissue infection sites, were genotyped, and pUSA03 was detected using polymerase chain reaction assays.

Investigators detected the pUSA03 subclone in about 29% of patients from both surveys, and, of these, 99% were men who have sex with men. Among homosexual men who were infected with the pUSA03 subclone of USA300, 39% (35 of 89) had infections that involved the buttocks and genitoperineal area, and 30% (27 of 89) had infections that involved the extremities.

In the San Francisco survey, being a man who has sex with men was the strongest predictor of infection with the pUSA03 subclone after controlling for the effects of a previous MRSA infection and for clindamycin use in the previous year.

Previous use of trimethoprim-sulfamethoxazole was significantly associated with pUSA03 subclone infection, but prior use of mupirocin and hospitalization in the previous year were not significant risk factors, the investigators reported at the meeting, which was sponsored by the American Society for Microbiology.

In the Boston cohort, multidrug-resistant USA300 carrying the pUSA03 plasmid was recovered exclusively among men having sex with men.

The percentage of USA300 resistant to multiple classes of commonly used antimicrobial agents, including beta-lactams, macrolides, clindamycin, tetracyclines, and mupirocin, varied in the surveys from location to location.

In San Francisco, 18% of USA300 isolates were multidrug-resistant, whereas in Boston, 48% of the isolates were multidrug-resistant, Dr. Diep said.

CHICAGO — A novel mammography system called stereoscopic digital mammography dramatically improved the accuracy of lesion detection in breast cancer screening, according to interim data from an ongoing trial in 1,093 women at high risk for developing breast cancer.

Stereoscopic full-field digital mammography significantly reduced the number of false-positive lesion detections by 49% and false-negative findings by 40%, compared with standard full-field digital mammography, David Getty, Ph.D., and his associates reported at the annual meeting of the Radiological Society of North America.

“Stereoscopic mammography is reducing false-positive reports by nearly one-half, and the implication would be that many fewer women would be recalled unnecessarily for diagnostic work-up, resulting in reduced health care costs and patient anxiety,” he said. “It is also reducing false-negative readings, especially for clustered calcifications, with the implication that detecting more true lesions will result in earlier detection of those that turn out to be cancer.”

A stereoscopic mammogram is created by acquiring two digital x-ray images separated by a rotation of the x-ray tube of about 6–10 degrees between the two acquisitions while the breast remains fixed in a compressed position. Dr. Getty compared the experience of reading a stereoscopic mammogram to watching 3-D movies while wearing red and green glasses.

The two images are presented simultaneously with crossed polarization on two LCD monitors separated by a sheet of glass coated with a material that is 50% reflective and 50% transmissive. This means the image presented on the lower, vertical monitor is transmitted through the glass and the image from the upper, angled monitor is reflected off the top surface of the glass plate. To view the two images, the radiologist wears passive polarized glasses with crosspolarized lenses so that the radiologist's left eye sees only the image on the lower monitor and the right eye sees only the image being reflected off the glass.

The 3-D display monitor used in the study was developed by Planar Systems Inc., Beaverton, Ore., and uses control software developed by Dr. Getty, a division scientist at BBN Technologies, Cambridge, Mass.

The stereoscopic system allows the radiologist to see the internal structure of the breast directly, in depth, which helps overcome the three main problems associated with standard mammography: masking of lesions, mimicry of lesions, and limited volumetric information. Normal breast tissue is separated away from the lesion in depth, thus increasing the lesion's conspicuousness. False positives are reduced because the elements of normal tissue aligned along the line of sight can be seen lying at different depths within the breast, so they don't mimic a focal abnormality. Finally, volumetric information is increased because the radiologist can directly view the 3-D structure of tissue and calcifications within the breast.

Women in the study, at Emory University's Breast Imaging Center in Atlanta, had a standard screening full-field digital exam then a stereoscopic exam consisting of the cranial-caudal and mediolateral oblique screening views. The exams were read independently by different radiologists.

So far, 259 abnormal findings have been identified by one or both modalities, with further clinical work-up exams showing 109 were true lesions and 150 were false positives. Standard mammography missed 40 of the 109 lesions, and stereoscopic mammography failed to detect 24, a 40% reduction in false-negative readings. Of calcified lesions, standard mammography missed nearly half (20 of 41), compared with 4 missed by stereoscopic mammography, a highly significant reduction. For specificity of lesion detection, standard mammography reported 103 of 150 false positives and stereoscopic mammography just 53, a highly significant 49% reduction.

Dr. David Getty wears cross-polarized lenses to view the 3-D image. Dr. David Getty/BBN Technologies

CHICAGO — A novel mammography system called stereoscopic digital mammography dramatically improved the accuracy of lesion detection in breast cancer screening, according to interim data from an ongoing trial in 1,093 women at high risk for developing breast cancer.

Stereoscopic full-field digital mammography significantly reduced the number of false-positive lesion detections by 49% and false-negative findings by 40%, compared with standard full-field digital mammography, David Getty, Ph.D., and his associates reported at the annual meeting of the Radiological Society of North America.

“Stereoscopic mammography is reducing false-positive reports by nearly one-half, and the implication would be that many fewer women would be recalled unnecessarily for diagnostic work-up, resulting in reduced health care costs and patient anxiety,” he said. “It is also reducing false-negative readings, especially for clustered calcifications, with the implication that detecting more true lesions will result in earlier detection of those that turn out to be cancer.”

A stereoscopic mammogram is created by acquiring two digital x-ray images separated by a rotation of the x-ray tube of about 6–10 degrees between the two acquisitions while the breast remains fixed in a compressed position. Dr. Getty compared the experience of reading a stereoscopic mammogram to watching 3-D movies while wearing red and green glasses.

The two images are presented simultaneously with crossed polarization on two LCD monitors separated by a sheet of glass coated with a material that is 50% reflective and 50% transmissive. This means the image presented on the lower, vertical monitor is transmitted through the glass and the image from the upper, angled monitor is reflected off the top surface of the glass plate. To view the two images, the radiologist wears passive polarized glasses with crosspolarized lenses so that the radiologist's left eye sees only the image on the lower monitor and the right eye sees only the image being reflected off the glass.

The 3-D display monitor used in the study was developed by Planar Systems Inc., Beaverton, Ore., and uses control software developed by Dr. Getty, a division scientist at BBN Technologies, Cambridge, Mass.

The stereoscopic system allows the radiologist to see the internal structure of the breast directly, in depth, which helps overcome the three main problems associated with standard mammography: masking of lesions, mimicry of lesions, and limited volumetric information. Normal breast tissue is separated away from the lesion in depth, thus increasing the lesion's conspicuousness. False positives are reduced because the elements of normal tissue aligned along the line of sight can be seen lying at different depths within the breast, so they don't mimic a focal abnormality. Finally, volumetric information is increased because the radiologist can directly view the 3-D structure of tissue and calcifications within the breast.

Women in the study, at Emory University's Breast Imaging Center in Atlanta, had a standard screening full-field digital exam then a stereoscopic exam consisting of the cranial-caudal and mediolateral oblique screening views. The exams were read independently by different radiologists.

So far, 259 abnormal findings have been identified by one or both modalities, with further clinical work-up exams showing 109 were true lesions and 150 were false positives. Standard mammography missed 40 of the 109 lesions, and stereoscopic mammography failed to detect 24, a 40% reduction in false-negative readings. Of calcified lesions, standard mammography missed nearly half (20 of 41), compared with 4 missed by stereoscopic mammography, a highly significant reduction. For specificity of lesion detection, standard mammography reported 103 of 150 false positives and stereoscopic mammography just 53, a highly significant 49% reduction.

Dr. David Getty wears cross-polarized lenses to view the 3-D image. Dr. David Getty/BBN Technologies

CHICAGO — A novel mammography system called stereoscopic digital mammography dramatically improved the accuracy of lesion detection in breast cancer screening, according to interim data from an ongoing trial in 1,093 women at high risk for developing breast cancer.

Stereoscopic full-field digital mammography significantly reduced the number of false-positive lesion detections by 49% and false-negative findings by 40%, compared with standard full-field digital mammography, David Getty, Ph.D., and his associates reported at the annual meeting of the Radiological Society of North America.

“Stereoscopic mammography is reducing false-positive reports by nearly one-half, and the implication would be that many fewer women would be recalled unnecessarily for diagnostic work-up, resulting in reduced health care costs and patient anxiety,” he said. “It is also reducing false-negative readings, especially for clustered calcifications, with the implication that detecting more true lesions will result in earlier detection of those that turn out to be cancer.”

A stereoscopic mammogram is created by acquiring two digital x-ray images separated by a rotation of the x-ray tube of about 6–10 degrees between the two acquisitions while the breast remains fixed in a compressed position. Dr. Getty compared the experience of reading a stereoscopic mammogram to watching 3-D movies while wearing red and green glasses.

The two images are presented simultaneously with crossed polarization on two LCD monitors separated by a sheet of glass coated with a material that is 50% reflective and 50% transmissive. This means the image presented on the lower, vertical monitor is transmitted through the glass and the image from the upper, angled monitor is reflected off the top surface of the glass plate. To view the two images, the radiologist wears passive polarized glasses with crosspolarized lenses so that the radiologist's left eye sees only the image on the lower monitor and the right eye sees only the image being reflected off the glass.

The 3-D display monitor used in the study was developed by Planar Systems Inc., Beaverton, Ore., and uses control software developed by Dr. Getty, a division scientist at BBN Technologies, Cambridge, Mass.

The stereoscopic system allows the radiologist to see the internal structure of the breast directly, in depth, which helps overcome the three main problems associated with standard mammography: masking of lesions, mimicry of lesions, and limited volumetric information. Normal breast tissue is separated away from the lesion in depth, thus increasing the lesion's conspicuousness. False positives are reduced because the elements of normal tissue aligned along the line of sight can be seen lying at different depths within the breast, so they don't mimic a focal abnormality. Finally, volumetric information is increased because the radiologist can directly view the 3-D structure of tissue and calcifications within the breast.

Women in the study, at Emory University's Breast Imaging Center in Atlanta, had a standard screening full-field digital exam then a stereoscopic exam consisting of the cranial-caudal and mediolateral oblique screening views. The exams were read independently by different radiologists.

So far, 259 abnormal findings have been identified by one or both modalities, with further clinical work-up exams showing 109 were true lesions and 150 were false positives. Standard mammography missed 40 of the 109 lesions, and stereoscopic mammography failed to detect 24, a 40% reduction in false-negative readings. Of calcified lesions, standard mammography missed nearly half (20 of 41), compared with 4 missed by stereoscopic mammography, a highly significant reduction. For specificity of lesion detection, standard mammography reported 103 of 150 false positives and stereoscopic mammography just 53, a highly significant 49% reduction.

Dr. David Getty wears cross-polarized lenses to view the 3-D image. Dr. David Getty/BBN Technologies

CHICAGO — There is no indication to test routinely for hetero-resistant vancomycin-intermediate Staphylococcus aureus (hVISA), Dr. Benjamin Howden said at the annual Interscience conference on Antimicrobial Agents and Chemotherapy.

S. aureus strains with reduced vancomycin susceptibility are an emerging and clinically important problem, because vancomycin is the primary antimicrobial agent used for treating methicillin-resistant S. aureus (MRSA) infections. S. aureus strains with vancomycin minimally inhibitory concentrations (MICs) of 2 or less, 4–8, or greater than 8 mcg/mL are defined as susceptible, intermediately resistant, or resistant, respectively, according to the Clinical and Laboratory Standards Institute.

Before January 2006, the susceptibility breakpoints were 4 or less, 8–16, or greater than 16 mcg/mL, but were revised to reflect a growing body of data indicating that S. aureus isolates with MICs of 4 mcg/mL are strongly associated with vancomycin treatment failure. Heterogeneous VISA strains fall into the susceptible category.

It's difficult to determine how common hVISA is because different groups use different criteria to define and detect hVISA, said Dr. Howden of the infectious diseases department, Austin Health, Melbourne. Unpublished data from his group, however, show that 65% of 1,500 isolates with an MIC of 2 mcg/mL were positive for hVISA. Also, several groups, including one from North Carolina (J. Antimicrob. Chemother. 2007;60:788–94), report an increasing proportion of vancomycin-susceptible MRSA blood isolates with a vancomycin MIC of 1 mcg/mL. This “MIC creep … means you will be seeing more hVISA over time,” he said.

Population analysis profiling (PAP) is considered the accepted standard test for detecting hVISA, but it is labor intensive and costly. Several other methods have been developed recently, with the Etest macromethod showing good sensitivity and specificity, compared with PAP, Dr. Howden said.

Another issue to be aware of when testing for hVISA is that it can emerge during failed vancomycin therapy. Dr. Howden recalled one patient who developed hVISA over 3 weeks of failed vancomycin therapy, which he defines as an S. aureus-positive blood culture after at least 7 days of vancomycin therapy or a sterile-site isolate positive for S. aureus after at least 21 days of vancomycin therapy. “It's not enough to test an initial clinical isolate, but later isolates as well,” he said.

A clear association exists between vancomycin treatment failure and the subsequent development of hVISA, but it's unclear if hVISA is associated with subsequent treatment failure. Clinical factors that can put patients at increased risk for vancomycin treatment failure include high bacterial load, persistent bacteremia, large undrained abscesses, bacterial endocarditis, and infected prosthetic devices.

Vancomycin failure has also been attributed to factors within the hVISA strain itself, including changes in the thickness and composition of the S. aureus cell wall; reduced susceptibility to vancomycin; and reduced RNAIII expression, autolytic activity, and biofilm formation. As to whether clinical vs. “bug” factors are more important, Dr. Howden said, “We believe it is probably a combination of both, and is what we consider the perfect clinical storm.”

Although much effort was spent in the past on screening all S. aureus isolates for hVISA, a more practical approach to MRSA and hVISA/VISA is to be wary of patients with high bacterial loads and high-risk disease such as deep abscess, prosthetic device infection, and endocarditis; to aim for high vancomycin serum levels (15–20 mcg/mL) in patients without proven, serious MRSA infection; and to debulk abscesses whenever possible. Finally, clinicians should be aware of the possibility of reduced susceptibility to other agents such as daptomycin and possibly tigecycline, said Dr. Howden, who declared no financial conflicts of interest.

CHICAGO — There is no indication to test routinely for hetero-resistant vancomycin-intermediate Staphylococcus aureus (hVISA), Dr. Benjamin Howden said at the annual Interscience conference on Antimicrobial Agents and Chemotherapy.

S. aureus strains with reduced vancomycin susceptibility are an emerging and clinically important problem, because vancomycin is the primary antimicrobial agent used for treating methicillin-resistant S. aureus (MRSA) infections. S. aureus strains with vancomycin minimally inhibitory concentrations (MICs) of 2 or less, 4–8, or greater than 8 mcg/mL are defined as susceptible, intermediately resistant, or resistant, respectively, according to the Clinical and Laboratory Standards Institute.

Before January 2006, the susceptibility breakpoints were 4 or less, 8–16, or greater than 16 mcg/mL, but were revised to reflect a growing body of data indicating that S. aureus isolates with MICs of 4 mcg/mL are strongly associated with vancomycin treatment failure. Heterogeneous VISA strains fall into the susceptible category.

It's difficult to determine how common hVISA is because different groups use different criteria to define and detect hVISA, said Dr. Howden of the infectious diseases department, Austin Health, Melbourne. Unpublished data from his group, however, show that 65% of 1,500 isolates with an MIC of 2 mcg/mL were positive for hVISA. Also, several groups, including one from North Carolina (J. Antimicrob. Chemother. 2007;60:788–94), report an increasing proportion of vancomycin-susceptible MRSA blood isolates with a vancomycin MIC of 1 mcg/mL. This “MIC creep … means you will be seeing more hVISA over time,” he said.

Population analysis profiling (PAP) is considered the accepted standard test for detecting hVISA, but it is labor intensive and costly. Several other methods have been developed recently, with the Etest macromethod showing good sensitivity and specificity, compared with PAP, Dr. Howden said.

Another issue to be aware of when testing for hVISA is that it can emerge during failed vancomycin therapy. Dr. Howden recalled one patient who developed hVISA over 3 weeks of failed vancomycin therapy, which he defines as an S. aureus-positive blood culture after at least 7 days of vancomycin therapy or a sterile-site isolate positive for S. aureus after at least 21 days of vancomycin therapy. “It's not enough to test an initial clinical isolate, but later isolates as well,” he said.

A clear association exists between vancomycin treatment failure and the subsequent development of hVISA, but it's unclear if hVISA is associated with subsequent treatment failure. Clinical factors that can put patients at increased risk for vancomycin treatment failure include high bacterial load, persistent bacteremia, large undrained abscesses, bacterial endocarditis, and infected prosthetic devices.

Vancomycin failure has also been attributed to factors within the hVISA strain itself, including changes in the thickness and composition of the S. aureus cell wall; reduced susceptibility to vancomycin; and reduced RNAIII expression, autolytic activity, and biofilm formation. As to whether clinical vs. “bug” factors are more important, Dr. Howden said, “We believe it is probably a combination of both, and is what we consider the perfect clinical storm.”

Although much effort was spent in the past on screening all S. aureus isolates for hVISA, a more practical approach to MRSA and hVISA/VISA is to be wary of patients with high bacterial loads and high-risk disease such as deep abscess, prosthetic device infection, and endocarditis; to aim for high vancomycin serum levels (15–20 mcg/mL) in patients without proven, serious MRSA infection; and to debulk abscesses whenever possible. Finally, clinicians should be aware of the possibility of reduced susceptibility to other agents such as daptomycin and possibly tigecycline, said Dr. Howden, who declared no financial conflicts of interest.

CHICAGO — There is no indication to test routinely for hetero-resistant vancomycin-intermediate Staphylococcus aureus (hVISA), Dr. Benjamin Howden said at the annual Interscience conference on Antimicrobial Agents and Chemotherapy.

S. aureus strains with reduced vancomycin susceptibility are an emerging and clinically important problem, because vancomycin is the primary antimicrobial agent used for treating methicillin-resistant S. aureus (MRSA) infections. S. aureus strains with vancomycin minimally inhibitory concentrations (MICs) of 2 or less, 4–8, or greater than 8 mcg/mL are defined as susceptible, intermediately resistant, or resistant, respectively, according to the Clinical and Laboratory Standards Institute.

Before January 2006, the susceptibility breakpoints were 4 or less, 8–16, or greater than 16 mcg/mL, but were revised to reflect a growing body of data indicating that S. aureus isolates with MICs of 4 mcg/mL are strongly associated with vancomycin treatment failure. Heterogeneous VISA strains fall into the susceptible category.

It's difficult to determine how common hVISA is because different groups use different criteria to define and detect hVISA, said Dr. Howden of the infectious diseases department, Austin Health, Melbourne. Unpublished data from his group, however, show that 65% of 1,500 isolates with an MIC of 2 mcg/mL were positive for hVISA. Also, several groups, including one from North Carolina (J. Antimicrob. Chemother. 2007;60:788–94), report an increasing proportion of vancomycin-susceptible MRSA blood isolates with a vancomycin MIC of 1 mcg/mL. This “MIC creep … means you will be seeing more hVISA over time,” he said.

Population analysis profiling (PAP) is considered the accepted standard test for detecting hVISA, but it is labor intensive and costly. Several other methods have been developed recently, with the Etest macromethod showing good sensitivity and specificity, compared with PAP, Dr. Howden said.

Another issue to be aware of when testing for hVISA is that it can emerge during failed vancomycin therapy. Dr. Howden recalled one patient who developed hVISA over 3 weeks of failed vancomycin therapy, which he defines as an S. aureus-positive blood culture after at least 7 days of vancomycin therapy or a sterile-site isolate positive for S. aureus after at least 21 days of vancomycin therapy. “It's not enough to test an initial clinical isolate, but later isolates as well,” he said.

A clear association exists between vancomycin treatment failure and the subsequent development of hVISA, but it's unclear if hVISA is associated with subsequent treatment failure. Clinical factors that can put patients at increased risk for vancomycin treatment failure include high bacterial load, persistent bacteremia, large undrained abscesses, bacterial endocarditis, and infected prosthetic devices.

Vancomycin failure has also been attributed to factors within the hVISA strain itself, including changes in the thickness and composition of the S. aureus cell wall; reduced susceptibility to vancomycin; and reduced RNAIII expression, autolytic activity, and biofilm formation. As to whether clinical vs. “bug” factors are more important, Dr. Howden said, “We believe it is probably a combination of both, and is what we consider the perfect clinical storm.”

Although much effort was spent in the past on screening all S. aureus isolates for hVISA, a more practical approach to MRSA and hVISA/VISA is to be wary of patients with high bacterial loads and high-risk disease such as deep abscess, prosthetic device infection, and endocarditis; to aim for high vancomycin serum levels (15–20 mcg/mL) in patients without proven, serious MRSA infection; and to debulk abscesses whenever possible. Finally, clinicians should be aware of the possibility of reduced susceptibility to other agents such as daptomycin and possibly tigecycline, said Dr. Howden, who declared no financial conflicts of interest.

CHICAGO — A second multicenter trial has shown that noninvasive CT angiography is highly accurate in assessing coronary artery disease when compared with conventional invasive angiography.

The per-vessel negative predictive value of 64-slice coronary CT angiography (CCTA) was 97% for identifying blockages greater than 50%, and 99% for blockages greater than 70%, when measured in 232 patients with typical or atypical chest pain in the Assessment by Coronary Computed Tomographic Angiography of Individuals Undergoing Invasive Coronary Angiography (ACCURACY) trial. Positive predictive values were 51% and 33%, respectively, Dr. James K. Min and his associates reported at the annual meeting of the Radiological Society of North America.

“The ACCURACY results [obtained] in a prospective, multicenter fashion definitively establish the high diagnostic accuracy and high negative predictive value of 64-detector-row CT angiography in chest pain patients with intermediate prevalence of coronary artery disease,” said Dr. Min, director of the cardiac CT laboratory at New York-Presbyterian Hospital in New York City.

The findings echo those of the recent Coronary Artery Evaluation Using 64-Row Multidetector Computed Tomography Angiography (CORE-64) trial, in which CT angiography had a 91% positive predictive value and an 83% negative predictive value for identifying significant coronary artery stenoses. CORE-64 was the first large, multicenter trial of the 64-slice technology for coronary angiography, but was criticized by some attendees at the annual scientific sessions of the American Heart Association where it was presented. Concerns were raised that the radiation dose from repeated CT scans could pose a potential cancer risk. No such concerns were raised at the radiology meeting.

To reduce the amount of radiation given to patients in the ACCURACY trial, investigators used a radiation-dose reduction algorithm called EKG modulation that reduces CT angiography radiation by about 40%, Dr. Min said in an interview. The radiation dose per patient was about 10–15 millisieverts (mSv), which is about twice that of an invasive coronary angiogram and about half that of a noninvasive thallium stress test.

Since the trial began, a new algorithm called perspective axial gating has been commercially released and is reported to reduce exposure by 90%, to about 2–4 mSv. Both algorithms work by activating the CT scanner during select parts of the cardiac cycle only, Dr. Min said. For comparison, New York City residents are exposed to about 3 mSv of radiation annually through background exposure.

Neither study used CT angiography for screening. “I believe very emphatically that the data to date don't support CT angiography as a screening tool at all,” Dr. Min said. “In asymptomatic patients, we don't have any data of what to do with the results, and if treatment benefits them.”

CT angiography is of greatest benefit for patients without known coronary disease who have low or intermediate pretest risk. “If you have a high pretest suspicion that someone has coronary artery disease, then direct progression to invasive coronary angiography or even myocardial perfusion imaging is probably a better alternative,” he said.

The ACCURACY trial was unique in that it included all coronary artery segments in its analysis and all patients irrespective of their baseline coronary calcium score. In the CORE-64 trial, stented segments were excluded, as were patients with a calcium score higher than 600. As a result, the ACCURACY findings of high diagnostic accuracy are even more impressive and representative of actual clinical usage of CCTA, Dr. Min said.

Between May 2006 and January 2007, ACCURACY investigators performed CCTA prior to conventional quantitative coronary angiography (QCA) on 232 patients who had typical or atypical chest pain and had been referred for evaluation at 16 U.S. centers. The images were obtained on a GE Healthcare LightSpeed VCT scanner, and analyzed at 15 different locations throughout the coronary tree. The investigators used equipment made by GE Healthcare, which sponsored the study. Dr. Min is on the speaker's bureau for GE Healthcare.

Three independent radiologists interpreted the CCTA images, and one independent radiologist interpreted the QCA images. No segments were excluded based on nonagreement between readers, and only one segment was debated among readers, Dr. Min said.

The patients' mean age was 57 years (range 31–82 years); 138 were male, 203 were white, and 13 were black, and their average body mass index was 31 kg/m

QCA detected 82 blockages greater than 50% in 55 patients and 31 blockages greater than 70% in 34 patients.

For noninvasive CCTA, per-patient sensitivity was 93% and specificity was 82% for blockages greater than 50%; sensitivity was 91% and specificity was 84% for blockages greater than 70%, Dr. Min said.

Additional analyses of the ACCURACY data are being conducted, including a comparison of CT angiography to historical single-photon emission computed tomography (SPECT) imaging, cost-effectiveness versus standard of care, incremental benefit of CT angiography beyond traditional coronary calcium scoring, and interreader, interpatient, and intersegment reliability.

CHICAGO — A second multicenter trial has shown that noninvasive CT angiography is highly accurate in assessing coronary artery disease when compared with conventional invasive angiography.

The per-vessel negative predictive value of 64-slice coronary CT angiography (CCTA) was 97% for identifying blockages greater than 50%, and 99% for blockages greater than 70%, when measured in 232 patients with typical or atypical chest pain in the Assessment by Coronary Computed Tomographic Angiography of Individuals Undergoing Invasive Coronary Angiography (ACCURACY) trial. Positive predictive values were 51% and 33%, respectively, Dr. James K. Min and his associates reported at the annual meeting of the Radiological Society of North America.

“The ACCURACY results [obtained] in a prospective, multicenter fashion definitively establish the high diagnostic accuracy and high negative predictive value of 64-detector-row CT angiography in chest pain patients with intermediate prevalence of coronary artery disease,” said Dr. Min, director of the cardiac CT laboratory at New York-Presbyterian Hospital in New York City.

The findings echo those of the recent Coronary Artery Evaluation Using 64-Row Multidetector Computed Tomography Angiography (CORE-64) trial, in which CT angiography had a 91% positive predictive value and an 83% negative predictive value for identifying significant coronary artery stenoses. CORE-64 was the first large, multicenter trial of the 64-slice technology for coronary angiography, but was criticized by some attendees at the annual scientific sessions of the American Heart Association where it was presented. Concerns were raised that the radiation dose from repeated CT scans could pose a potential cancer risk. No such concerns were raised at the radiology meeting.

To reduce the amount of radiation given to patients in the ACCURACY trial, investigators used a radiation-dose reduction algorithm called EKG modulation that reduces CT angiography radiation by about 40%, Dr. Min said in an interview. The radiation dose per patient was about 10–15 millisieverts (mSv), which is about twice that of an invasive coronary angiogram and about half that of a noninvasive thallium stress test.

Since the trial began, a new algorithm called perspective axial gating has been commercially released and is reported to reduce exposure by 90%, to about 2–4 mSv. Both algorithms work by activating the CT scanner during select parts of the cardiac cycle only, Dr. Min said. For comparison, New York City residents are exposed to about 3 mSv of radiation annually through background exposure.

Neither study used CT angiography for screening. “I believe very emphatically that the data to date don't support CT angiography as a screening tool at all,” Dr. Min said. “In asymptomatic patients, we don't have any data of what to do with the results, and if treatment benefits them.”

CT angiography is of greatest benefit for patients without known coronary disease who have low or intermediate pretest risk. “If you have a high pretest suspicion that someone has coronary artery disease, then direct progression to invasive coronary angiography or even myocardial perfusion imaging is probably a better alternative,” he said.

The ACCURACY trial was unique in that it included all coronary artery segments in its analysis and all patients irrespective of their baseline coronary calcium score. In the CORE-64 trial, stented segments were excluded, as were patients with a calcium score higher than 600. As a result, the ACCURACY findings of high diagnostic accuracy are even more impressive and representative of actual clinical usage of CCTA, Dr. Min said.

Between May 2006 and January 2007, ACCURACY investigators performed CCTA prior to conventional quantitative coronary angiography (QCA) on 232 patients who had typical or atypical chest pain and had been referred for evaluation at 16 U.S. centers. The images were obtained on a GE Healthcare LightSpeed VCT scanner, and analyzed at 15 different locations throughout the coronary tree. The investigators used equipment made by GE Healthcare, which sponsored the study. Dr. Min is on the speaker's bureau for GE Healthcare.

Three independent radiologists interpreted the CCTA images, and one independent radiologist interpreted the QCA images. No segments were excluded based on nonagreement between readers, and only one segment was debated among readers, Dr. Min said.

The patients' mean age was 57 years (range 31–82 years); 138 were male, 203 were white, and 13 were black, and their average body mass index was 31 kg/m

QCA detected 82 blockages greater than 50% in 55 patients and 31 blockages greater than 70% in 34 patients.

For noninvasive CCTA, per-patient sensitivity was 93% and specificity was 82% for blockages greater than 50%; sensitivity was 91% and specificity was 84% for blockages greater than 70%, Dr. Min said.

Additional analyses of the ACCURACY data are being conducted, including a comparison of CT angiography to historical single-photon emission computed tomography (SPECT) imaging, cost-effectiveness versus standard of care, incremental benefit of CT angiography beyond traditional coronary calcium scoring, and interreader, interpatient, and intersegment reliability.

CHICAGO — A second multicenter trial has shown that noninvasive CT angiography is highly accurate in assessing coronary artery disease when compared with conventional invasive angiography.

The per-vessel negative predictive value of 64-slice coronary CT angiography (CCTA) was 97% for identifying blockages greater than 50%, and 99% for blockages greater than 70%, when measured in 232 patients with typical or atypical chest pain in the Assessment by Coronary Computed Tomographic Angiography of Individuals Undergoing Invasive Coronary Angiography (ACCURACY) trial. Positive predictive values were 51% and 33%, respectively, Dr. James K. Min and his associates reported at the annual meeting of the Radiological Society of North America.

“The ACCURACY results [obtained] in a prospective, multicenter fashion definitively establish the high diagnostic accuracy and high negative predictive value of 64-detector-row CT angiography in chest pain patients with intermediate prevalence of coronary artery disease,” said Dr. Min, director of the cardiac CT laboratory at New York-Presbyterian Hospital in New York City.

The findings echo those of the recent Coronary Artery Evaluation Using 64-Row Multidetector Computed Tomography Angiography (CORE-64) trial, in which CT angiography had a 91% positive predictive value and an 83% negative predictive value for identifying significant coronary artery stenoses. CORE-64 was the first large, multicenter trial of the 64-slice technology for coronary angiography, but was criticized by some attendees at the annual scientific sessions of the American Heart Association where it was presented. Concerns were raised that the radiation dose from repeated CT scans could pose a potential cancer risk. No such concerns were raised at the radiology meeting.

To reduce the amount of radiation given to patients in the ACCURACY trial, investigators used a radiation-dose reduction algorithm called EKG modulation that reduces CT angiography radiation by about 40%, Dr. Min said in an interview. The radiation dose per patient was about 10–15 millisieverts (mSv), which is about twice that of an invasive coronary angiogram and about half that of a noninvasive thallium stress test.

Since the trial began, a new algorithm called perspective axial gating has been commercially released and is reported to reduce exposure by 90%, to about 2–4 mSv. Both algorithms work by activating the CT scanner during select parts of the cardiac cycle only, Dr. Min said. For comparison, New York City residents are exposed to about 3 mSv of radiation annually through background exposure.

Neither study used CT angiography for screening. “I believe very emphatically that the data to date don't support CT angiography as a screening tool at all,” Dr. Min said. “In asymptomatic patients, we don't have any data of what to do with the results, and if treatment benefits them.”

CT angiography is of greatest benefit for patients without known coronary disease who have low or intermediate pretest risk. “If you have a high pretest suspicion that someone has coronary artery disease, then direct progression to invasive coronary angiography or even myocardial perfusion imaging is probably a better alternative,” he said.

The ACCURACY trial was unique in that it included all coronary artery segments in its analysis and all patients irrespective of their baseline coronary calcium score. In the CORE-64 trial, stented segments were excluded, as were patients with a calcium score higher than 600. As a result, the ACCURACY findings of high diagnostic accuracy are even more impressive and representative of actual clinical usage of CCTA, Dr. Min said.

Between May 2006 and January 2007, ACCURACY investigators performed CCTA prior to conventional quantitative coronary angiography (QCA) on 232 patients who had typical or atypical chest pain and had been referred for evaluation at 16 U.S. centers. The images were obtained on a GE Healthcare LightSpeed VCT scanner, and analyzed at 15 different locations throughout the coronary tree. The investigators used equipment made by GE Healthcare, which sponsored the study. Dr. Min is on the speaker's bureau for GE Healthcare.

Three independent radiologists interpreted the CCTA images, and one independent radiologist interpreted the QCA images. No segments were excluded based on nonagreement between readers, and only one segment was debated among readers, Dr. Min said.

The patients' mean age was 57 years (range 31–82 years); 138 were male, 203 were white, and 13 were black, and their average body mass index was 31 kg/m

QCA detected 82 blockages greater than 50% in 55 patients and 31 blockages greater than 70% in 34 patients.

For noninvasive CCTA, per-patient sensitivity was 93% and specificity was 82% for blockages greater than 50%; sensitivity was 91% and specificity was 84% for blockages greater than 70%, Dr. Min said.

Additional analyses of the ACCURACY data are being conducted, including a comparison of CT angiography to historical single-photon emission computed tomography (SPECT) imaging, cost-effectiveness versus standard of care, incremental benefit of CT angiography beyond traditional coronary calcium scoring, and interreader, interpatient, and intersegment reliability.

CHICAGO — Equivalent or better asthma control using combination therapy may be achieved with less budesonide/formoterol than with fluticasone/salmeterol in the first year of use, Samy Suissa, Ph.D., said at the annual meeting of the American College of Chest Physicians.

He and Dr. Pierre Ernst of McGill University Health Center, Montreal, reported an observational study in 23,075 patients, aged 4–95 years, with asthma, who were first-time users of budesonide/formoterol (6,918) or fluticasone/salmeterol (16,157). The therapies are the only combination treatments available in a single inhaler.

The investigators used the United Kingdom's General Research Database, which includes 6 million patients from about 450 practices, to identify patients who received their first budesonide/formoterol or fluticasone/salmeterol prescription from May 2001 (when both therapies became available in the United Kingdom) to December 2005.

To emulate a prospective randomized trial, they conducted both intent-to-treat and persistent-treatment analyses on the frequency of prescriptions and health care events in the year after the first prescription. They adjusted for covariates measured during the year before this prescription.

A range of dosages and inhalers was used in each group. Patients with chronic obstructive pulmonary disease were excluded, said Dr. Suissa. He and Dr. Ernst have received research grants and speaker fees from, and have served on advisory boards for, AstraZeneca Pharmaceuticals LP, which manufactures budesonide/formoterol as Symbicort, and GlaxoSmithKline Inc., which makes fluticasone/salmeterol as Advair.

At baseline, budesonide/formoterol patients had a generally less severe asthma profile, compared with fluticasone/salmeterol patients, said Dr. Suissa, director of McGill's pharmacoepidemiology research unit, and professor of epidemiology, biostatistics, and medicine.

Budesonide/formoterol patients used fewer short-acting (83% vs. 85%) and long-acting (23% vs. 36%) β-agonists, and fewer oral (28% vs. 32%) and inhaled (47% vs. 57%) corticosteroids, and were less likely to have an asthma-related hospital visit (1% vs. 1.7%). Both groups saw a general provider an average of 10 times in the year before their combination therapy prescription. The mean ages were 44 years (budesonide/formoterol) and 43 years (fluticasone/salmeterol). In the intent-to-treat analysis, budesonide/formoterol patients received 14% fewer prescriptions for their study drug than did fluticasone/salmeterol patients, 8% fewer prescriptions for other asthma medications, and 9% fewer antibiotic prescriptions.

Persistent treatment (two prescriptions with a gap of less than 7 days between them), averaged 3.1 months in the budesonide/formoterol group and 2.8 months in the fluticasone/salmeterol group. After adjustment for baseline determinants, duration of persistent use was 15% longer for budesonide/formoterol patients. In the persistent-treatment analysis, which covered only the 3 months on average of continuous use, budesonide/formoterol patients got 11% fewer prescriptions for their therapy than did fluticasone/salmeterol patients, 8% fewer prescriptions for other asthma medications, and 11% fewer antibiotic prescriptions.

ELSEVIER GLOBAL MEDICAL NEWS

CHICAGO — Equivalent or better asthma control using combination therapy may be achieved with less budesonide/formoterol than with fluticasone/salmeterol in the first year of use, Samy Suissa, Ph.D., said at the annual meeting of the American College of Chest Physicians.

He and Dr. Pierre Ernst of McGill University Health Center, Montreal, reported an observational study in 23,075 patients, aged 4–95 years, with asthma, who were first-time users of budesonide/formoterol (6,918) or fluticasone/salmeterol (16,157). The therapies are the only combination treatments available in a single inhaler.

The investigators used the United Kingdom's General Research Database, which includes 6 million patients from about 450 practices, to identify patients who received their first budesonide/formoterol or fluticasone/salmeterol prescription from May 2001 (when both therapies became available in the United Kingdom) to December 2005.

To emulate a prospective randomized trial, they conducted both intent-to-treat and persistent-treatment analyses on the frequency of prescriptions and health care events in the year after the first prescription. They adjusted for covariates measured during the year before this prescription.

A range of dosages and inhalers was used in each group. Patients with chronic obstructive pulmonary disease were excluded, said Dr. Suissa. He and Dr. Ernst have received research grants and speaker fees from, and have served on advisory boards for, AstraZeneca Pharmaceuticals LP, which manufactures budesonide/formoterol as Symbicort, and GlaxoSmithKline Inc., which makes fluticasone/salmeterol as Advair.

At baseline, budesonide/formoterol patients had a generally less severe asthma profile, compared with fluticasone/salmeterol patients, said Dr. Suissa, director of McGill's pharmacoepidemiology research unit, and professor of epidemiology, biostatistics, and medicine.

Budesonide/formoterol patients used fewer short-acting (83% vs. 85%) and long-acting (23% vs. 36%) β-agonists, and fewer oral (28% vs. 32%) and inhaled (47% vs. 57%) corticosteroids, and were less likely to have an asthma-related hospital visit (1% vs. 1.7%). Both groups saw a general provider an average of 10 times in the year before their combination therapy prescription. The mean ages were 44 years (budesonide/formoterol) and 43 years (fluticasone/salmeterol). In the intent-to-treat analysis, budesonide/formoterol patients received 14% fewer prescriptions for their study drug than did fluticasone/salmeterol patients, 8% fewer prescriptions for other asthma medications, and 9% fewer antibiotic prescriptions.

Persistent treatment (two prescriptions with a gap of less than 7 days between them), averaged 3.1 months in the budesonide/formoterol group and 2.8 months in the fluticasone/salmeterol group. After adjustment for baseline determinants, duration of persistent use was 15% longer for budesonide/formoterol patients. In the persistent-treatment analysis, which covered only the 3 months on average of continuous use, budesonide/formoterol patients got 11% fewer prescriptions for their therapy than did fluticasone/salmeterol patients, 8% fewer prescriptions for other asthma medications, and 11% fewer antibiotic prescriptions.

ELSEVIER GLOBAL MEDICAL NEWS

CHICAGO — Equivalent or better asthma control using combination therapy may be achieved with less budesonide/formoterol than with fluticasone/salmeterol in the first year of use, Samy Suissa, Ph.D., said at the annual meeting of the American College of Chest Physicians.

He and Dr. Pierre Ernst of McGill University Health Center, Montreal, reported an observational study in 23,075 patients, aged 4–95 years, with asthma, who were first-time users of budesonide/formoterol (6,918) or fluticasone/salmeterol (16,157). The therapies are the only combination treatments available in a single inhaler.

The investigators used the United Kingdom's General Research Database, which includes 6 million patients from about 450 practices, to identify patients who received their first budesonide/formoterol or fluticasone/salmeterol prescription from May 2001 (when both therapies became available in the United Kingdom) to December 2005.

To emulate a prospective randomized trial, they conducted both intent-to-treat and persistent-treatment analyses on the frequency of prescriptions and health care events in the year after the first prescription. They adjusted for covariates measured during the year before this prescription.

A range of dosages and inhalers was used in each group. Patients with chronic obstructive pulmonary disease were excluded, said Dr. Suissa. He and Dr. Ernst have received research grants and speaker fees from, and have served on advisory boards for, AstraZeneca Pharmaceuticals LP, which manufactures budesonide/formoterol as Symbicort, and GlaxoSmithKline Inc., which makes fluticasone/salmeterol as Advair.

At baseline, budesonide/formoterol patients had a generally less severe asthma profile, compared with fluticasone/salmeterol patients, said Dr. Suissa, director of McGill's pharmacoepidemiology research unit, and professor of epidemiology, biostatistics, and medicine.

Budesonide/formoterol patients used fewer short-acting (83% vs. 85%) and long-acting (23% vs. 36%) β-agonists, and fewer oral (28% vs. 32%) and inhaled (47% vs. 57%) corticosteroids, and were less likely to have an asthma-related hospital visit (1% vs. 1.7%). Both groups saw a general provider an average of 10 times in the year before their combination therapy prescription. The mean ages were 44 years (budesonide/formoterol) and 43 years (fluticasone/salmeterol). In the intent-to-treat analysis, budesonide/formoterol patients received 14% fewer prescriptions for their study drug than did fluticasone/salmeterol patients, 8% fewer prescriptions for other asthma medications, and 9% fewer antibiotic prescriptions.

Persistent treatment (two prescriptions with a gap of less than 7 days between them), averaged 3.1 months in the budesonide/formoterol group and 2.8 months in the fluticasone/salmeterol group. After adjustment for baseline determinants, duration of persistent use was 15% longer for budesonide/formoterol patients. In the persistent-treatment analysis, which covered only the 3 months on average of continuous use, budesonide/formoterol patients got 11% fewer prescriptions for their therapy than did fluticasone/salmeterol patients, 8% fewer prescriptions for other asthma medications, and 11% fewer antibiotic prescriptions.

ELSEVIER GLOBAL MEDICAL NEWS

CHICAGO — The pUSA03 subclone of the USA300 strain is emerging as a major cause of community-acquired methicillin-resistant Staphylococcus aureus, especially in men who have sex with men.

The new strain is likely spread through skin-to-skin, sexual contact, Binh An Diep, Ph.D., and his associates reported in a poster at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.

USA300 has recently emerged as the predominant cause of community-acquired MRSA and skin and soft-tissue infections in the United States.

A population-based study that involved all MRSA infections treated at 9 of 10 participating medical centers in San Francisco showed the incidence of the pUSA03 subclone was 171 cases per 100,000 in one San Francisco ZIP code. That compares with 57 cases per 100,000 in three other city ZIP codes and 47 cases per 100,000 in four other city ZIP codes, Dr. Diep and his associates reported.

The high-incidence ZIP code (94114) corresponds to the Castro district, which has the highest concentration of gay men in the United States. The Castro neighborhood is an affluent area with an average annual income of $90,000, making it less likely that the majority of infected individuals were IV drug users, Dr. Diep, of the University of California, San Francisco, observed in an interview.

“The mechanism seems to be one of skin-to-skin contact, and having very vigorous perianal sex that creates a breach of the skin barrier leading to perianal abscess,” he said. A previous report in six heterosexual patients supports this largely unrecognized method of transmission for community-acquired MRSA (Clin. Infect. Dis. 2007;44:410–3).

“The take-home message is really personal hygiene,” Dr. Diep said. “Because MRSA is now spread skin-to-skin, wearing a condom won't help. So you have to be very careful and bathe yourself very well.”

The investigators also reviewed the medical charts of 183 patients treated at San Francisco General's Hospital Positive Health Program, an outpatient HIV clinic, and the charts of 130 patients treated at Boston's Fenway Community Health, which also has an outpatient clinic. MRSA isolates, cultured predominantly from skin and soft-tissue infection sites, were genotyped, and pUSA03 was detected using polymerase chain reaction assays.

The pUSA03 subclone was detected in about 29% of patients from both surveys, and, of these, 99% were men who have sex with men. Among gay men who were infected with the pUSA03 subclone of USA300, 39% (35 of 89) had infections that involved the buttocks and genitoperineal area, and 30% (27 of 89) had infections that involved the extremities.

In the San Francisco survey, being a man who has sex with men was the strongest predictor of infection with the pUSA03 subclone after controlling for the effects of a previous MRSA infection and for clindamycin use in the previous year.

Previous use of trimethoprimsulfamethoxazole was significantly associated with pUSA03 subclone infection, but prior use of mupirocin and hospitalization in the previous year were not significant risk factors, the investigators reported at the meeting, which was sponsored at the American Society for Microbiology.

In the Boston cohort, multidrug-resistant USA300 carrying the pUSA03 plasmid was recovered exclusively among men having sex with men.

The percentage of USA300 resistant that were to multiple classes of commonly used antimicrobial agents, including β-lactams, macrolides, clindamycin, tetracyclines, and mupirocin, varied in the surveys by location. In San Francisco, 18% of USA300 isolates were multidrug-resistant, whereas in Boston, 48% of the isolates were multidrug-resistant, Dr. Diep said.

CHICAGO — The pUSA03 subclone of the USA300 strain is emerging as a major cause of community-acquired methicillin-resistant Staphylococcus aureus, especially in men who have sex with men.

The new strain is likely spread through skin-to-skin, sexual contact, Binh An Diep, Ph.D., and his associates reported in a poster at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.

USA300 has recently emerged as the predominant cause of community-acquired MRSA and skin and soft-tissue infections in the United States.

A population-based study that involved all MRSA infections treated at 9 of 10 participating medical centers in San Francisco showed the incidence of the pUSA03 subclone was 171 cases per 100,000 in one San Francisco ZIP code. That compares with 57 cases per 100,000 in three other city ZIP codes and 47 cases per 100,000 in four other city ZIP codes, Dr. Diep and his associates reported.

The high-incidence ZIP code (94114) corresponds to the Castro district, which has the highest concentration of gay men in the United States. The Castro neighborhood is an affluent area with an average annual income of $90,000, making it less likely that the majority of infected individuals were IV drug users, Dr. Diep, of the University of California, San Francisco, observed in an interview.

“The mechanism seems to be one of skin-to-skin contact, and having very vigorous perianal sex that creates a breach of the skin barrier leading to perianal abscess,” he said. A previous report in six heterosexual patients supports this largely unrecognized method of transmission for community-acquired MRSA (Clin. Infect. Dis. 2007;44:410–3).

“The take-home message is really personal hygiene,” Dr. Diep said. “Because MRSA is now spread skin-to-skin, wearing a condom won't help. So you have to be very careful and bathe yourself very well.”

The investigators also reviewed the medical charts of 183 patients treated at San Francisco General's Hospital Positive Health Program, an outpatient HIV clinic, and the charts of 130 patients treated at Boston's Fenway Community Health, which also has an outpatient clinic. MRSA isolates, cultured predominantly from skin and soft-tissue infection sites, were genotyped, and pUSA03 was detected using polymerase chain reaction assays.

The pUSA03 subclone was detected in about 29% of patients from both surveys, and, of these, 99% were men who have sex with men. Among gay men who were infected with the pUSA03 subclone of USA300, 39% (35 of 89) had infections that involved the buttocks and genitoperineal area, and 30% (27 of 89) had infections that involved the extremities.

In the San Francisco survey, being a man who has sex with men was the strongest predictor of infection with the pUSA03 subclone after controlling for the effects of a previous MRSA infection and for clindamycin use in the previous year.

Previous use of trimethoprimsulfamethoxazole was significantly associated with pUSA03 subclone infection, but prior use of mupirocin and hospitalization in the previous year were not significant risk factors, the investigators reported at the meeting, which was sponsored at the American Society for Microbiology.

In the Boston cohort, multidrug-resistant USA300 carrying the pUSA03 plasmid was recovered exclusively among men having sex with men.

The percentage of USA300 resistant that were to multiple classes of commonly used antimicrobial agents, including β-lactams, macrolides, clindamycin, tetracyclines, and mupirocin, varied in the surveys by location. In San Francisco, 18% of USA300 isolates were multidrug-resistant, whereas in Boston, 48% of the isolates were multidrug-resistant, Dr. Diep said.

CHICAGO — The pUSA03 subclone of the USA300 strain is emerging as a major cause of community-acquired methicillin-resistant Staphylococcus aureus, especially in men who have sex with men.

The new strain is likely spread through skin-to-skin, sexual contact, Binh An Diep, Ph.D., and his associates reported in a poster at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.

USA300 has recently emerged as the predominant cause of community-acquired MRSA and skin and soft-tissue infections in the United States.

A population-based study that involved all MRSA infections treated at 9 of 10 participating medical centers in San Francisco showed the incidence of the pUSA03 subclone was 171 cases per 100,000 in one San Francisco ZIP code. That compares with 57 cases per 100,000 in three other city ZIP codes and 47 cases per 100,000 in four other city ZIP codes, Dr. Diep and his associates reported.

The high-incidence ZIP code (94114) corresponds to the Castro district, which has the highest concentration of gay men in the United States. The Castro neighborhood is an affluent area with an average annual income of $90,000, making it less likely that the majority of infected individuals were IV drug users, Dr. Diep, of the University of California, San Francisco, observed in an interview.

“The mechanism seems to be one of skin-to-skin contact, and having very vigorous perianal sex that creates a breach of the skin barrier leading to perianal abscess,” he said. A previous report in six heterosexual patients supports this largely unrecognized method of transmission for community-acquired MRSA (Clin. Infect. Dis. 2007;44:410–3).

“The take-home message is really personal hygiene,” Dr. Diep said. “Because MRSA is now spread skin-to-skin, wearing a condom won't help. So you have to be very careful and bathe yourself very well.”

The investigators also reviewed the medical charts of 183 patients treated at San Francisco General's Hospital Positive Health Program, an outpatient HIV clinic, and the charts of 130 patients treated at Boston's Fenway Community Health, which also has an outpatient clinic. MRSA isolates, cultured predominantly from skin and soft-tissue infection sites, were genotyped, and pUSA03 was detected using polymerase chain reaction assays.

The pUSA03 subclone was detected in about 29% of patients from both surveys, and, of these, 99% were men who have sex with men. Among gay men who were infected with the pUSA03 subclone of USA300, 39% (35 of 89) had infections that involved the buttocks and genitoperineal area, and 30% (27 of 89) had infections that involved the extremities.

In the San Francisco survey, being a man who has sex with men was the strongest predictor of infection with the pUSA03 subclone after controlling for the effects of a previous MRSA infection and for clindamycin use in the previous year.

Previous use of trimethoprimsulfamethoxazole was significantly associated with pUSA03 subclone infection, but prior use of mupirocin and hospitalization in the previous year were not significant risk factors, the investigators reported at the meeting, which was sponsored at the American Society for Microbiology.

In the Boston cohort, multidrug-resistant USA300 carrying the pUSA03 plasmid was recovered exclusively among men having sex with men.

The percentage of USA300 resistant that were to multiple classes of commonly used antimicrobial agents, including β-lactams, macrolides, clindamycin, tetracyclines, and mupirocin, varied in the surveys by location. In San Francisco, 18% of USA300 isolates were multidrug-resistant, whereas in Boston, 48% of the isolates were multidrug-resistant, Dr. Diep said.