Urinary tract infections: resistance to fluoroquinolones in E. coli

Introduction: Escherichia coli is the most common pathogen isolated in urinary tract infections.An optimal antibiotic treatment of UTIs will contribute substantially to limit the use of antibiotics to overcome antimicrobial resistance.The purpose of this study was to determine the degree of resistance of E. coli to fluoroquinolones. Methods: 1765 E. coli strains collected from nosocomial patients were considered. Of these 571 were isolated during the period from 01/01/2007 to 31/12/2007, 785 during the period from 01-01-2008 to 31-12-208, and 409 during the period from 01-01-2009 to 30/06/2009. Urine samples were cultured on agar plates of Columbia with 5% sheep blood and Mac Conkey. Strain identification and antibiotic susceptibility tests were carried out by automatic equipment (Valiscan-Siemens). The antibiotics tested were: ciprofloxacin, levofloxacin and norfloxacin. Results: The evolution of ciprofloxacin resistance ranged from 40% among the strains collected in the year 2007 to 43% among those collected during the first half of 2009.The other fluoroquinolones showed similar trend. Conclusions: The rate of resistance of E. coli to fluoroquinolones was slightly increased during the period of observation, a finding similar to that reported in other surveys.