Prevalence and determinants of antibiotic resistance in faecal Escherichia coli among unselected patients attending general practitioners in Southwest Germany.

PURPOSE: Widespread use of antibiotics is thought to be the main reason for the world-wide increase in antibiotic resistance. Although a great majority of antibiotics are prescribed outside hospitals, little is known about the prevalence and determinants of antibiotic resistance in the general population.
METHODS: Escherichia coli (E. coli) was cultured from and minimal inhibitory concentrations against six commonly prescribed antibiotic substances were tested in 750 stool samples of 484 unselected, consecutive outpatients aged 40-74 years attending general practitioners. Odds ratios (OR) and their 95% confidence intervals (CI) for the association between potential risk factors and the prevalence of antibiotic resistance were estimated using generalised estimating equations.
RESULTS: Prevalence of E. coli resistance against ampicillin, doxycycline, cotrimoxazole or quinolones was 24%. Current antibiotic use was strongly associated with antibiotic resistance, adjusted OR: 11.1, 95% CI: 2.3-53, but antibiotic resistance was unaffected by antibiotic use stopped weeks before. Recent hospitalisations were the only other significant predictor of an increased prevalence of resistance.
CONCLUSIONS: The strong association between current use of antibiotics and colonisation with antibiotic resistant E. coli suggests a major role for selection of resistant strains while using antibiotics that seem to be quickly reversible, though. Copyright 2003 John Wiley & Sons, Ltd.