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.