Risk Factors for Ciprofloxacin-Resistant Escherichia coli Strains in Pediatric Patients with Acute Urinary Tract Infection

ABSTRACT

PURPOSE: Previous exposure to fluoroquinolone is an important risk factor for acquiring resistant strains of microorganisms. However, the mechanisms of fluoroquinolone resistance in Escherichia coli from pediatric patients with urinary tract infection (UTI) are not well defined because fluoroquinolone prescription for children is not permitted around the world. We investigated the risk factors for ciprofloxacin-resistant E. coli isolates from the urine of pediatric patients with UTI. MATERIALS AND METHODS: Data from 72 patients who showed > or =10(5) E. coli colony-forming units in urine culture were retrospectively collected from a university hospital between June 2006 and June 2009. The minimum inhibitory concentration of ciprofloxacin resistance was determined by the agar dilution method on Mueller-Hinton agar. RESULTS: The rates of E. coli resistance to ciprofloxacin, cefazolin, ampicillin, co-trimoxazole, and fosfomycin were 8.3%, 20.8%, 77.7%, 25%, and 0%, respectively. Differences in sex, age intervals, and previous antimicrobial use in recent years were significantly associated with ciprofloxacin resistance, whereas admission level, the presence of fever, and the type of UTI were not. In addition, female gender, previous antimicrobial use, and older age significantly increased the risk for ciprofloxacin resistance in a univariate analysis. Only co-trimoxazole resistance was positively associated with ciprofloxacin resistance, whereas resistance to other antimicrobials was not. CONCLUSIONS: Even though the incidence was not high, ciprofloxacin resistance was found in E. coli from pediatric UTIs. Because the characteristics of ciprofloxacin resistance in pediatric patients are not well defined, further study of the mechanism of acquiring ciprofloxacin resistance in children is needed.