Detection of drug-resistant Escherichia coli in patients with complicated cystitis: Analysis of risk factors

Objectives: To determine the prevalence and risk factors for isolation of drug-resistant Escherichia coli (E. coli) in patients with complicated cystitis. Methods: We analyzed 170 patients with complicated cystitis and urine culture was positive for E. coli in all of them. Detailed clinical features were identified and risk factors for isolation of drug-resistant E. coli were determined. Results: The drug susceptibilities of 170 isolates to levofloxacin and cefotaxime or cefpirome were 77% and 96%, respectively. Fluoroquinolone-resistant E. coli (FQREc) was detected at least once in 39 patients. Prior use of fluoroquinolones within 1 month, between 1 and 3 months, and hospitalization were risk factors for FQREc infection (P < 0.05), with odds ratios of 24 (95% confidence interval [CI] 6.4-89), 4.7 (95% CI 1.8-12), and 3.1 (95% CI 1.4-6.8), respectively. All six organisms resistant to cephems were extended-spectrum beta-lactamase (ESBL)-producing E. coli. The isolation of ESBL-producing E. coli tended to be more frequent in patients who were hospitalized (P < 0.05), with an odds ratio of 7.9 (95% CI 1.4-45). There was no significant correlation between growth rate of ESBL-producing E. coli and prior use of antibiotics. Conclusions: The frequencies of FQREc and ESBL-producing E. coli were 23% and 4%, respectively. Prior use of fluoroquinolones within 3 months and hospitalization were risk factors for FQREc. Hospitalization was a risk factor for ESBL-producing E. coli infection.