Vol.57 No.S-1 March 2009
In vitro antimicrobial activity of tebipenem
Pharmaceutical Research Center, Meiji Seika Kaisha, Ltd., 760 Morooka, Kohoku-ku, Yokohama, Kanagawa, Japan
Abstract
We compared the in vitro antibacterial activity of tebipenem(TBPM), an active form of a novel oral carbapenem, tebipenem pivoxil, against standard strains and clinical isolates to that of cefditoren(CDTR), faropenem(FRPM), levofloxacin(LVFX) and other antibiotics. The MIC of TBPM was 0.5 μg/mL or less against aerobic Gram-positive and Gram-negative bacteria except for enterococci and glucose nonfermentative bacteria such as Pseudomonas aeruginosa. The MIC of TBPM against anaerobes was 1 μg/mL or less. TBPM also showed a potent activity against clinical isolates. The in vitro activity of TBPM against Streptococcus pneumoniae, it should be noted , was the most potent among 12 reference antibiotics, and TBPM completely inhibited the growth of all strains including penicillin-resistant S. pneumoniae at 0.12 μg/mL or less. The in vitro activity of TBPM against Haemophilus influenzae, including β-lactamase-nonproducing ampicillin-resistant H. influenzae, was weaker than that of CDTR and LVFX, but stronger than that of FRPM. The bactericidal activity of TBPM against S. pneumoniae and H. influenzae was comparable to that of LVFX and CDTR. TBPM showed a potent activity against class A, including extended-spectrum β-lactamases, and class C β-lactamase-transformed strains, but not against class B β-lactamase (metallo-β-lactamase)-transformed strains among isogenic laboratory strains. TBPM showed a post-antibiotic effect against both Staphylococcus aureus and Escherichia coli for 0.8 h after 1 h exposure at a concentration of 4×MIC of TBPM. We concluded that TBPM showed a potent activity against major causative pathogens of community-acquired respiratory tract infections.
Key word
tebipenem, antimicrobial activity, post-antibiotic effect
Received
October 7, 2008
Accepted
December 15, 2008
Jpn. J. Chemother. 57 (S-1): 1-14, 2009
