Susceptibility of group B streptococci to 16 beta-lactam antibiotics, including new penicillin and cephalosporin derivatives.
The susceptibility of 100 group B streptococci to 16 beta-lactam antibiotics was tested by agar dilution. Penicillin G and N-formimidoyl thienamycin were the most active agents tested, both having a 90% minimal inhibitory concentration (MIC90) of 0.06 microgram/ml. Ceftriaxone, cefotaxime, cefamandole, and SCH 29482 were almost as active, all having an MIC90 of 0.12 microgram/ml, and ampicillin, cephalothin, and mezlocillin all had an MIC90 of 0.25 microgram/ml. The MIC90 for piperacillin, cefoperazone, and ceftazidime was 0.5 microgram/ml. Least active were carbenicillin, ticarcillin, cefoxitin, and moxalactam, with MIC90s of 1, 2, 4, and 8 micrograms/ml, respectively. No penicillin-tolerant strains were detected.
D000900:Anti-Bacterial Agents / Q000134:cerebrospinal fluid / Q000494:pharmacology* / Q000627:therapeutic use; D002511:Cephalosporins / Q000494:pharmacology*; D006801:Humans; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000188:drug therapy; D008581:Meningitis / Q000188:drug therapy; D008826:Microbial Sensitivity Tests; D010406:Penicillins / Q000494:pharmacology*; D013292:Streptococcus agalactiae / Q000187:drug effects*
D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D010406:Penicillins