High rates of quinolone resistance among urinary tract infections in the ED

Abstract

Objectives The objectives of this study are to examine antibiotic resistance rates and to determine appropriate empiric oral antibiotic for patients with urinary tract infections (UTIs) evaluated and discharged from the ED. Methods A retrospective, single-institution chart review study from August 2008 to March 2009 was conducted. Adult patients seen in the ED with UTI were identified for study inclusion from review of microbiology records. Hospitalized or asymptomatic bacteriuria cases were excluded. Health care-associated (HA)–UTI was defined as UTI with indwelling urinary catheters, health care exposure, or urologic procedures within 3 months. Prevalence of causative bacteria, antibiotic resistance rates, and risk factors for quinolone resistance were determined. Results There were 337 eligible patients with 83% women. The most common uropathogens among 357 bacterial isolates were Escherichia coli (71%) and Klebsiella spp. (9%). Overall levofloxacin resistance rate was 17%. Resistance rates for HA-UTIs were significantly greater than those for community-associated–UTI: levofloxacin, 38% vs 10%; trimethoprim-sulfamethoxazole, 26% vs 17%; amoxicillin, 53% vs 45%; and amoxicillin-clavulanate, 16% vs 6%. Nitrofurantoin resistance rates were similar (9%). Independent risk factors for levofloxacin resistance were long-term medical conditions (adjusted odds ratio [aOR], 4.23; P = .001), HA-UTI (aOR, 2.56; P = .006), and prior quinolone use within 1 week (aOR, 14.90; P = .02) and within 1 to 4 weeks (aOR, 4.62; P = .04). Conclusions We report high rates of quinolone resistance in ED patients with UTIs at our institution. For patients with risk factors for quinolone resistance, empiric therapy with cephalosporins or nitrofurantoin may be preferred. Urine culture and susceptibility testing should be performed to guide definitive therapy for HA-UTIs.