Conventional and molecular epidemiology of trimethoprim-sulfamethoxazole resistance among urinary Escherichia coli isolates.

BACKGROUND: Antibiotic resistance is increasing in Escherichia coli, the most common cause of urinary tract infections, but its epidemiology has not been well described. We evaluated the epidemiology of trimethoprim-sulfamethoxazole-resistant E. coli in a large, public health care system in Denver, Colorado. METHODS: Outpatients with E. coli urinary tract infections during the first 6 months of 1998 were evaluated retrospectively. A prospective study was then performed to confirm the rate of trimethoprim-sulfamethoxazole resistance. We used several strain-typing methods (pulsed-field gel electrophoresis, ribotyping, serotyping) to evaluate the molecular epidemiology of the resistance. RESULTS: The rate of trimethoprim-sulfamethoxazole resistance was similar in the retrospective (24% [161/681]) and prospective (23% [30/130]) phases of the study (P = 0.89). Almost all trimethoprim-sulfamethoxazole-resistant strains (98%) were resistant to at least one other antibiotic. Risk factors for infection with a resistant strain included age < or =3 years, Hispanic ethnicity, recent travel outside the United States, and a prior urinary tract infection. However, rates of resistance were >15% among nearly all of the subgroups. Most strains had high-level resistance (>1000 microg/mL) to trimethoprim-sulfamethoxazole. Of the 23 resistant isolates evaluated, 10 (43%) belonged to the clone A group. There was no correlation between conventional epidemiologic characteristics and the molecular mechanism of resistance or strain type. CONCLUSION: Resistance to trimethoprim-sulfamethoxazole among E. coli isolates among patients in a Denver public health care system is common, with high rates of resistance even among patients without risk factors.

Education level, primary language, and comprehension of the informed consent process.

TO OBTAIN INFORMATION ON HOW PERSONS from diverse backgrounds experience the informed consent process, we surveyed adults with a wide variety of educational levels and different primary languages (English, Spanish, or Vietnamese) who had recently enrolled in a study requiring written informed consent. Of the 100 participants, 62 were non-White, 43 had less than a high school education, and 60 had a primary language other than English. The median score for comprehension was 62% (IQR 50-76%); the median satisfaction score was 86% (IQR 71-100%). In multivariate analysis, only educational level was significantly associated with comprehension and satisfaction with the informed consent process (p < 0.001). Comprehension and satisfaction with the informed consent process were markedly lower among persons with lower educational levels.

Widespread emergence of methicillin resistance in community-acquired Staphylococcus aureus infections in Denver.

BACKGROUND: Increasing rates of methicillin resistance among out-patient Staphylococcus aureus infections led us to assess the epidemiology and outcome of a local outbreak. METHODS: A retrospective cohort study of outpatient skin and soft tissue infections due to S aureus in 2003. RESULTS: From 2002 to mid-2004, the percentage of outpatient S aureus isolates resistant to methicillin increased from 6 to 45%. In multivariate analysis, only male sex and age greater than 18 years were associated with methicillin resistance. Methicillin resistance was common (>15%) among isolates from patients in nearly all subgroups evaluated. Pulsed field gel electrophoresis showed isolates related to USA 300, but methicillin-resistant strains had unusually high rates of quinolone resistance. CONCLUSIONS: A single strain of methicillin-resistant S aureus is responsible for the increase in skin infections in outpatients without traditional risk factors for infection with an antibiotic-resistant strain. In areas with high rates of methicillin-resistant S aureus outpatient infections, we recommend non-beta-lactam antibiotics for initial treatment of skin and soft tissue infections.