Copyright © 1997, American Society for Microbiology NOTES In Vitro Evaluation of BO-3482, a Novel Dithiocarbamate Carbapenem with Activity against

BO-3482, a dithiocarbamate carbapenem, inhibited clinical isolates of methicillin-resistant staphylococci (MRS) at 6.25 mg/ml (MIC at which 90 % of isolates tested are inhibited [MIC90]), while the MIC90 of imipen-em was>100 mg/ml. BO-3482 was generally less active than imipenem against methicillin-susceptible Staphy-lococcus aureus, streptococci, enterococci, and gram-negative bacteria, although BO-3482 showed better activity (MIC90) than imipenem against Enterococcus faecium, Haemophilus influenzae, Proteus mirabilis, and Clostridium difficile. The affinities (50 % inhibitory concentrations) of BO-3482 for penicillin-binding protein (PBP) PBP 2* of MRS and PBP 5 of E. faecium (both PBPs have low affinities for ordinary b-lactam antibiotics) were 3.8 and 20 mg/ml, respectively, reflecting the greater activity of BO-3482 against MRS than against E. faecium. Carbapenem antibiotics are used frequently for the treat-ment of various bacterial infections because of their broad spectrum of action that encompasses Pseudomonas aeruginosa. However, the carbapenems currently in use lack activity against methicillin-resistant staphylococci (MRS), which has caused serious concern in clinics worldwide (1, 13). Although vancomycin has been used for the management of infection