Vol.57 No.S-1 March 2009
In vitro tebipenem activity against anaerobic bacteria
Division of Anaerobe Research, Gifu University Life Science Research Center, 1-1 Yanagido, Gifu, Japan
Abstract
We compared the in vitro activity of tebipenem(TBPM), an active metabolite of the new oral carbapenem tebipenem pivoxil to that of imipenem, cefditoren, clavulanate-amoxicillin, and clindamycin against a variety of anaerobic bacteria and a small number of facultative anaerobic bacteria (61 reference species). TBPM had a broad spectrum of activity against Gram-positive and Gram-negative anaerobe reference strains, inhibiting most tested strains at 0.5 μg/mL or less. TBPM also showed potent activity against 547 clinical isolates. Excluding Peptostreptococcus anaerobius, the TBPM MIC90 for anaerobic Gram-positive cocci, Clostridium perfringens, Veillonella spp., Prevotella spp., Porphyromonas spp., and Fusobacterium spp. was 0.25 μg/mL or less. For imipenem-susceptible strains in the Bacteroides fragilis group, TBPM showed good activity with a MIC90 of 0.5 to 2 μg/mL. Increasing the inoculum size had little effect on TBPM MIC against B. fragilis strains, although imipenem MIC against these strains increased 4- to 16-fold when the inoculum size was changed from 104 to 107 CFU/spot. TBPM was hydrolyzed by metallo-β-lactamase but was quite stable against type 2e β-lactamases extracted from B. fragilis. TBPM Ki against type 2e β-lactamases was as low as those of imipenem, indicating TBPM's potent antagonistic effect against enzyme activity.
Key word
tebipenem, antimicrobial activity, anaerobe
Received
October 7, 2008
Accepted
January 9, 2009
Jpn. J. Chemother. 57 (S-1): 30-37, 2009
