RISK FACTORS FOR AND IMPACT OF AMBULATORY URINARY TRACT INFECTIONS CAUSED BY HIGH MIC-

Coincident with the increasing use of fluoroquinolones (FQs) as the first-line agent for treatment of urinary tract infections (UTIs) in adults, the prevalence of high MIC fluoroquinolone susceptible E. coli (high MIC-FQSEC) which are the E. coli isolates with reduced susceptibility to FQs has increased substantially. The high MIC-FQSEC strains may serve as an important reservoir for FQ resistance in that treatment of these organisms with a FQ has been associated with future emergence of resistance. To establish an effective program for controlling emergence of FQ resistance, it is necessary to understand the risk factors for, and impact of infection caused by high MIC-FQSEC. To identify risk factors for high MIC-FQ susceptibility, we conducted a case-control study of female subjects with UTIs caused by FQSEC at outpatient services within University of Pennsylvania Health System, Philadelphia. A total of 1836 subjects with low MIC-FQSEC UTI (CASE) and 165 subjects with high MIC-FQSEC UTIs (CONTROL) were enrolled into our study. Independent risk factors for high MIC-FQ included Asian race, having renal diseases and previous exposure to nitrofurantoin. To determine the impact of high MIC-FQ susceptibility, we conducted a retrospective cohort study of female subjects with ambulatory FQSEC UTIs who were treated with FQ therapy. We enrolled 246 subjects into th