[Etiology and antimicrobial susceptibility among uropathogens causing community-acquired lower urinary tract infections: a nationwide surveillance study].

INTRODUCTION: Knowledge of antimicrobial susceptibility patterns is required to prescribe empirical therapy and formulate guidelines for the treatment of community-acquired urinary tract infections. This multicenter study assesses the etiology and antimicrobial susceptibility of the main community-acquired uropathogens in Spain.
METHODS: Between March and July 2002, a prospective, multicenter study was conducted in 15 microbiology laboratories located in nine autonomous regions. Each laboratory used its standard methods for sample processing and culture, bacterial identification and susceptibility testing.
RESULTS: A total of 2724 isolates were recovered from outpatients with lower urinary tract infections. The most frequent pathogen found was Escherichia coli (73%), followed by Proteus spp. (7.4%), Klebsiella spp. (6.6%) and Enterococcus spp. (4.8%). The susceptibility rates of E. coli were 97.9% for fosfomycin, 95.8% for cefixime, 94.3% for nitrofurantoin, 90.8% for amoxicillin-clavulanic acid and 77.2% for ciprofloxacin. E. coli resistance to fluoroquinolones was significantly higher in men (28.9% vs. 19% in women; P < 0.001), elderly patients (33.7% in 80 years or older vs. 7.1% in 40 years or younger; P < 0.001), complicated infections (24.8% vs. 13.7% in non-complicated; P < 0.001) and some regions (> 32% in Andalusia, Aragon and Castilla-Leon vs. 9.2% in Galicia).
CONCLUSIONS: E. coli was the main uropathogen in outpatients. Almost all E. coli isolates were susceptible to fosfomycin, cefixime and nitrofurantoin. Overall fluoroquinolone resistance was near 23%, but this rate varied significantly according to sex, age, type of urinary infection, and geographic region. This information should be considered when empirical therapy is recommended or prescribed in Spain.