title: In vitro and in vivo antibacterial activities of MT-141, a new semisynthetic cephamycin, compared with those of five cephalosporins.
abstract: The in vitro and in vivo antibacterial activities of MT-141 were compared with those of cefoxitin, cefmetazole, moxalactam, cefotaxime, and cefoperazone. The MICs of MT-141 for 90% of bacterial isolates were lower than the reference drugs against clinical isolates of Campylobacter jejuni, Clostridium difficile, and Bacteroides fragilis, whereas against clinical isolates of other gram-positive, gram-negative, and anaerobic bacteria, the MICs of MT-141 were similar to or higher than those of the reference drugs. In contrast, the bactericidal activity of MT-141 after 6- and 24-h exposures was superior to all of the reference drugs against 9 to 10 of the 12 bacterial strains studied, including Escherichia coli, Klebsiella pneumoniae, Salmonella enteritidis, indol-positive Proteus species, Serratia marcescens, Yersinia enterocolitica, Pseudomonas cepacia, and Clostridium perfringens. In the treatment of systemic infections in mice, MT-141 was again superior against 9 of the 12 strains tested, showing a good correlation with the bactericidal activity. It was found that the 50% effective doses of the six cephalosporins studied correlated better with the MBCs than with the MICs. As the serum levels of MT-141 in mice after subcutaneous administration were similar to those of the reference drugs, it was concluded that the bactericidal activity of MT-141 was a dominant factor in its in vivo activity.
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D001419:Bacteria / Q000187:drug effects*; D001424:Bacterial Infections / Q000188:drug therapy; D002511:Cephalosporins / Q000494:pharmacology*; D002513:Cephamycins / Q000494:pharmacology*; D006207:Half-Life; D007700:Kinetics; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008826:Microbial Sensitivity Tests
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D002513:Cephamycins; C046079:cefminox