Prevalence of and Risk Factors for Levofloxacin-Resistant E. coli Isolated from Outpatients with Urinary Tract Infection

PURPOSE: Levofloxacin has been widely used because of its broad spectrum and excellent penetration of the prostate. But levofloxacin-resistant Escherichia coli (E.coli) has been reported all over the world. We analyzed the annual levofloxacin resistance of E. coli and its risk factors. MATERIALS AND METHODS: From 2005 to 2009, we retrospectively analyzed patients who had undergone a urine analysis and a urine culture at the Outpatient Section of the Department of Urology of Kwangju Christian Hospital. Among them, we chose 509 patients infected by E. coli and evaluated the resistance rate to levofloxacin and its risk factors. RESULTS: The annual rates of levofloxacin resistance of E. coli were 29.49% in 2005, 26.51% in 2006, 40.21% in 2007, 43.20% in 2008, and 31.75% in 2009. A close correlation with the resistance rate was shown in cases that had underlying neurogenic bladder (p=0.002, odds ratio [OR]=4.236), a history of ciprofloxacin (p<0.001, OR=3.753) and levofloxacin (p<0.001, OR=2.996) administration for at least 48 hours in the past year, urolithiasis (p=0.003, OR=3.317), and older age (p<0.001, OR=1.027). CONCLUSIONS: This study from 2005 to 2009 showed that the levofloxacin resistance rates of E. coli were high at over 25%. The risk factors that affected the levofloxacin resistance rates of E. coli were underlying neurogenic bladder, ciprofloxacin administration history, urolithiasis, levofloxacin administration history, and older age. Levofloxacin should be prescribed cautiously in patients with these risk factors until the pathogen is identified.