Beta-lactam susceptibilities and prevalence of ESBL-producing isolates among more than 5000 European Enterobacteriaceae isolates.

In vitro susceptibility to 15 beta-lactam antibiotics was evaluated using Enterobacteriaceae isolated during the SENTRY Antimicrobial Surveillance Program. Piperacillin/tazobactam was the most active penicillin against Escherichia coli, Proteus mirabilis, Klebsiella oxytoca and Klebsiella pneumoniae (94.9%, 98.3%, 87.4% and 82.9% of isolates susceptible). Of the cephalosporins, cefepime was most effective against Escherichia coli, Proteus mirabilis and Enterobacter cloacae (99.2%, 96.3% and 95.2% of isolates susceptible, respectively) and cefoxitin against Klebsiella oxytoca and Klebsiella pneumoniae (98.6% and 95.6% of isolates susceptible). Carbapenems had excellent activity (> or =99.5% of all isolates). ESBL-production was confirmed with the ESBL-Etest and disk diffusion test in 1.3% of Escherichia coli isolates, 18.4% of Klebsiella pneumoniae, 12.6% of Klebsiella oxytoca and 5.3% of Proteus mirabilis isolates.