Antibiotic prescribing intensity and community UTI resistance: a cross-sectional ecological study.

Background: Antibiotic overuse is associated with antimicrobial resistance (AMR). It is unclear whether community AMR is driven by overall antibiotic use or by high levels of repeated (intense) use by individual patients.

Aim: To determine the association between high antibiotic prescribing intensity (all antibiotic prescriptions; any indication), and rates of UTI resistance among patients within small communities.

Design & setting: Repeated cross-sectional ecological analysis of geographical areas (population averaging 1500) from 2012-2015 using anonymised primary care data and urine cultures.

Method: For each area, we compared the percentage of antibiotic-prescribed patients who received≥5 prescriptions/3 years or≥4 prescriptions/year, with subsequent or same year UTI resistance rates. We also compared 'Average Daily Quantities' of all antibiotics prescribed, with UTI resistance rates, per year, per area. Results were adjusted for co-variates and analysed at area level using mixed effects logistic regression.

Results: Of 196,513 patients prescribed antibiotics in 69 areas, 16% were prescribed intensively (≥5 prescriptions in 3 years), receiving almost 30% of prescriptions. Of 12 308 confirmed UTI specimens (80% Escherichia Coli), 65% were resistant to at least one antibiotic (amoxicillin; cefalexin; ciprofloxacin; trimethoprim; nitrofurantoin). We found no significant association between high intensity 'any' antibiotic prescribing (same year/two preceding years) or overall 'any' antibiotic prescribing (same year) and UTI resistance.

Conclusion: We found no relationship between concurrent high intensity 'any' antibiotic prescribing, and UTI resistance rates in small urban communities, pre-covid. Individual patient use of multiple antibiotics, even at high intensity, may not be an independent risk factor for community UTI resistance.