Resistenza ai fluorochinoloni in Escherichia coli isolati da infezioni delle vie urinarie (IVU) in pazienti ospedalizzati in unità di terapia intensiva (UTI).

Abstract

Background: Fluoroquinolones are an important class of antibiotics for the treatment of urinary tract infections that have axcellent activity against Escherichia coli, one of the most frequently encountered pathogens. Several European studies have reported an increase of resistance to quinolones among uropathogenic E. coli. We conducted this study to update our knowledge on this evolution. Materials and methods: We evaluated the resistance phenotype of 203 clinical strains of E. coli collected from urine specimens. The following antimicrobial agents were tested: ampicillin, amoxiciclin-clavulanate, piperacillintazobactam, cefamandole, cefotaxime, ceftazidime, cefepime, aztreonam, imipenem, trimethoprimsulfamethoxazole, gentamicin, amikacin, ciprofloxacin, pipemidic acid, norfloxacin, nitrofurantoin. Disk diffusion tests were carried out as suggested by the CLSI (2006); strains were assigned to the susceptibility categories (susceptible, intermediate and resistant) interpreting results according to the established breakpoints. Results: Resistance to quinolones (pipemidic acid, norfloxacin and ciprofloxacin) was about of 45% and resistance to ampicillin, trimethoprim-sulfamethoxazole was 57. 1% and 55. 2%, respectively. Resistance rates less than 5% was found for cefepime, amikacin and imipenem. Conclusions: This study confirms the evolution through resistance to quinolones of uropathogenic E. coli isolates. The selective pressure exerted by fluoroquinolones may influence this evolution. Therapeutic alternatives, surveillance, and restriction of fluoroquinolones use are needed to control this spread of resistance.

Keywords

• uropathogenic Escherichia coli, fluoroquinolones resistance, ciprofloxacin, norfloxacin, pipemidic acid.