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.