Antimicrobial activity of doripenem and other carbapenems against gram-negative pathogens from Korea

A total of 950 gram-negative bacterial isolates from patients with bacteremia and urinary tract infections were collected from tertiary-care hospitals in Korea. In vitro antimicrobial susceptibility testing was performed using broth microdilution test according to Clinical and Laboratory Standards Institute protocol. In general, carbapenems such as doripenem, imipenem, and meropenem were very active against Enterobacteriaceae, Moraxella catarrhalis, Pseudomonas aeruginosa, and Acinetobacter sp. isolates. Doripenem was more potent than imipenem against most Enterobacteriaceae species except Proteus spp. based on minimum inhibitory concentration (MIC)(50) and MIC(90). In addition, doripenem displayed similar activity to meropenem but was superior to imipenem against ceftazidime-resistant Enterobacteriaceae isolates. For P. aeruginosa and Acinetobacter spp. isolates, MIC(50)s of doripenem were 1 and 0.5 mg/L, respectively, which were the same with those of meropenem but two- to fourfold lower than those of imipenem (both 2 mg/L). On the basis of the in vitro data, we conclude that doripenem has equivalent or more activity than other carbapenems such as imipenem and meropenem against most gram-negative pathogens from Korea. Thus, doripenem may be a promising new antimicrobial agent for the treatment of infections caused by gram-negative pathogens in Korea.