Etiology and antibiotic susceptibility patterns of bacteria collected from urinary tract infections in the ASL3 in Genoa

An epidemiological study addressed to identify the pathogens collected from urine samples and their antibiotic susceptibility patterns was conducted. From January 2008 to May 2009 56,435 urine samples were processed in the Clinical Microbiological Laboratory of the ASL3 in Genoa. Materials and methods. Urine samples were firstly screened by automated equipment Uroquik (ALIFAX).All urine cultures with microbial ≥105 CFU / ml were seeded on Chromagar Orientation (BD) and incubated at 37 ° C °.The identification of the isolates and the evaluation of their susceptibility to antibiotics were determined by the automated system Vitek 2 (bioMérieux). Results. About 33% (18,543) of the urine samples gave positive results.The number and frequency of the microorganisms collected was: 13,379 (72%) Gram-negative including 9179 (69%) E.coli, 1382 (10%) Klebsiella spp, 1209 (9%) Proteus spp, 445 (3%) Pseudomonas spp, and other species 1164 (9%), 4942 (27%) Gram positive which included 3615 (73%) Enterococcus spp, 821 (17%) Staphylococcus spp, 506 (10% ) Streptococcus spp and 222 (1%) fungi. In E. coli the incidence of susceptible strains ranged between 90-96% for gentamicin, fosfomycin, nitrofurantoin, piperacillin-tazobactam, between 87-89% for the cefepime, cefotaxime, ceftazidime, about 70% for quinolones ciprofloxacin, norfloxacin, and trimethoprim-sulfamethoxazole, 62% for piperacillin, about 50% to ampicillin. For Klebsiella spp and Proteus spp the percentage of susceptible strains ranged from 95-99% to piperacillin-tazobactam, gentamicin, and respectively 93% and between 68-52% for third-generation cephalosporins cefotaxime and ceftazidime and fluoroquinolones ciprofloxacin and norfloxacin. Conclusions. Present findings indicate that among the Enterobacteriaceae, E. coli, cause most of UTI and in vitro resulted susceptible various antibiotics.There was an increased resistance to fluoroquinolones among community-acquired E. coli and Proteus spp.A periodical epidemiological study will be necessary to monitor the evolution toward resistance to antibiotics of the strains collected from urinary tract infections.