Antibacterial prescribing and antibacterial resistance in English general practice: cross sectional study

Objective To quantify the relation between community based antibacterial pr escribing and antibacterial resistance in community acquired disease. Design Cross sectional study of antibacterial prescribing and antibacterial resistance of routine isolates within individual practices and primary car e groups. Setting 405 general practices (38 groups) in south west and north west Engl and. Main outcome measures Correlation between antibacterial prescribing and res istance for urinary coliforms and Streptococcus pneumoniae. Results Antibacterial resistance in urinary coliform isolates is common but the Correlation with prescribing rates was relatively low for individual p ractices (ampicillin and amoxicillin r(s) = 0.20, P = 0.001; trimethoprim. r(e) = 0.24, P = 0.0001) and primary care groups (ampicillin and amoxicilli n r(s) = 0.44, P = 0.05; trimethoprim r(s) = 0.31, P = 0.09). Regression co efficients were also low; a practice prescribing 20% less ampicillin and am oxicillin than average would have about 1% fewer resistant isolates (0.94/1 00; 95% confidence interval 0.02 to 1.85). Resistance of S pneumoniae to bo th penicillin and erythromycin remains uncommon, and no clear relation with prescribing was found. Conclusions Routine microbiological isolates should not be used for surveil lance of antibacterial resistance in the community or for monitoring the ou tcome of any change in antibacterial prescribing by general practitioners. Trying to reduce the overall level of antibiotic prescribing in UK general practice may not be the most effective strategy for reducing resistance in the community.