Infections caused by multiply drug resistant organisms such as extended spectrum beta-lactamase (ESBL) producing Escherichia coli and Klebsiella pneumoniae are increasing. Carbapenems (imipenem ve meropenem) are the antibiotics commonly used to treat these agents. Th e aim of this paper to determine the in-vitro activity of ertapenem, which is the newest carbapenem, for ESBL-producing E. coli ve K. pneumoniae isolates.

Th e bacteria were identified by conventional methods and Vitek-2 automated system. Th e antimicrobial susceptibility of antibiotics were tested by Kirby-Bauer disk diff usion method according to CLSI criteria. ESBL production were detected using cefotaxim/cefotaxim-clavulanate disks.

A total of 390 isolates (300 E. coli, 90 K. pneumoniae) were studied. Ertapenem resistance was detected in 10 E. coli (%3) and 12 K. pneumoniae (%13) strains. Two of E. coli and four of K. pneumoniae strains were also resistant to imipenem. Amikacin was the most susceptible agents for ESBL-producing isolates aft er carbapenem. High resistant rate to ciprofloksasin and trimethoprim-sulfamethoxazole were observed.

Ertapenem showed high in-vitro activity against E. coli and K. pneumoniae isolates. Th ese results suggest that ertapenem may be an good alternative for the treatment of infections caused by ESBL-producing isolates.