Antistaphylococcal activity and beta-lactamase resistance of newer cephalosporins.
Four newer cephalosporins (cefazolin, cefamandole, SK&F 59962, and cefoxitin) were investigated for determination of their antistaphylococcal activity and relative stability to staphylococcal beta-lactamase (penicillinase). Crude preparations of beta-lactamase from recent clinical isolates of Staphylococcus aureus were used. Cefamandole and SK&F 59962 were highly active against both large and small inocula of staphylococci and were resistant to staphylococcal beta-lactamase. Cefoxitin, although resistant to beta-lactamase, possessed less antibacterial potency but was still approximately as active as methicillin. Cefazolin was somewhat more susceptible to staphylococcal beta-lactamase than the other three agents and resembled cephaloridine in this respect. With minor exceptions, a correlation was found between the susceptibility of different agents to beta-lactamase and the magnitude of the effect of inoculum size when the drugs were tested against large and small inocula of staphylococci.
D000581:Amidohydrolases / Q000096:biosynthesis*; D002510:Cephalosporinase / Q000096:biosynthesis*; D002511:Cephalosporins / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D006868:Hydrolysis; D008826:Microbial Sensitivity Tests; D010400:Penicillin G / Q000008:administration & dosage / Q000037:antagonists & inhibitors; D010403:Penicillin Resistance; D013203:Staphylococcal Infections / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000254:growth & development
D002511:Cephalosporins; D000581:Amidohydrolases; D002510:Cephalosporinase; D010400:Penicillin G