Vol.53 No.S-1 July 2005

In vitro activity of doripenem, a 1β-methylcarbapenem, against anaerobic bacteria

Kaori Tanaka and Kunitomo Watanabe

Division of Anaerobe Research, Gifu University Life Science Research Center,
1-1 Yanagido, Gifu, Japan

Abstract

In vitro activity of doripenem (DRPM), a 1β-methylcarbapenem, was compared to that of imipenem (IPM), meropenem (MEPM), biapenem (BIPM), and clindamycin (CLDM) against a variety of anaerobic bacteria and a small number of facultative anaerobic bacteria (68 reference strains and 477 clinical isolates).
DRPM had a broad spectrum against gram-positive and gram-negative reference strains of anaerobes, inhibiting many anaerobic bacterial strains at 0.78 μg/mL or less. The MIC of DRPM for most reference strains was distributed one- or two- fold higher than that of IPM and MEPM, and one- fold lower than BIPM. For clinical strains, DRPM also showed potent activity. The MIC₉₀ of DRPM for pigmented and non-pigmented Prevotella, Fusobacterium spp., anaerobic gram-positive cocci except for Peptostreptococcus anaerobius, and Clostridium perfringens was 0.39 μg/mL or less. For Bacteroides fragilis and Bacteroides thetaiotaomicron, DRPM showed good activity with a MIC₉₀ of 0.78 μg/mL. Stability of DRPM to 6 β-lactamases with distinct substrate specificity extracted from 4 strains of B. fragilis and 2 strains of P. bivia was examined.
DRPM was hydrolyzed with metallo-β-lactamase but quite stable with other β-lactamases.

Key word

doripenem, carbapenem, antibacterial activity, anaerobe

Received

January 24, 2005

Accepted

March 1, 2005

Jpn. J. Chemother. 53 (S-1): 24-31, 2005