Risk factors for resistance to ciprofloxacin in community-acquired urinary tract infections due to Escherichia coli in an elderly population

Background: Antimicrobial resistance to ciprofloxacin is rising worldwide, especially in bacteria causing urinary tract infections (UTIs). Prudent use of current antibiotic drugs is therefore necessary. Objectives: We analysed (modifiable) risk factors for ciprofloxacin-resistant Escherichia coli. Methods: Urinary cultures of UTIs caused by E. coli were collected from participants in the Rotterdam Study, a prospective cohort study in an elderly population, and analysed for susceptibility to ciprofloxacin. Multivariate logistic regression was performed to investigate several possible risk factors for resistance. Results: Ciprofloxacin resistance in 1080 E. coli isolates was 10.2%. Multivariate analysis showed that higher age (OR 1.03; 95% CI 1.00-1.05) and use of two (OR 5.89; 95% CI 3.45-10.03) and three or more (OR 3.38; 95% CI 1.92-5.97) prescriptions of fluoroquinolones were associated with ciprofloxacin resistance, while no association between fluoroquinolone use more than 1 year before culture and ciprofloxacin resistance could be demonstrated. Furthermore, a high intake of pork (OR 3.68; 95% CI 1.36-9.99) and chicken (OR 2.72; 95% CI 1.08-6.85) and concomitant prescription of calcium supplements (OR 2.51; 95% CI 1.20-5.22) and proton pump inhibitors (OR 2.04; 95% CI 1.18-3.51) were associated with ciprofloxacin resistance. Conclusions: Ciprofloxacin resistance in community-acquired UTI was associated with a high intake of pork and chicken and with concomitant prescription of calcium supplements and proton pump inhibitors. Modification of antibiotic use in animals as well as temporarily stopping the prescription of concomitant calcium and proton pump inhibitors need further evaluation as strategies to prevent ciprofloxacin resistance.