title: Morphological alterations of Staphylococcus aureus and Streptococcus pyogenes exposed to cefdinir, a new oral broad-spectrum cephalosporin.
abstract: Affinity for penicillin-binding proteins (PBPs) and the morphological alteration of Staphylococcus aureus 209-P JC and Streptococcus pyogenes C-203 exposed to cefdinir were studied. Although cefdinir was bactericidal against both strains, the extent of the decrease in colony-forming units (CFU) was similar in a fairly wide range of concentrations. Transmission electron microscopy of S. aureus 209-P JC revealed that cefdinir induced thickening of the cross wall and frequent cell lysis at low concentrations. The lytic sites were seen at the site of septum formation. In S. pyogenes C-203, cefdinir induced thickening of the peripheral wall and cross wall, and protoplast-like cells were observed during the incubation period. Cefdinir showed high affinity for all PBPs of S. aureus 209-P JC and S. pyogenes C-203. The drastic changes in the morphology of S. aureus and S. pyogenes were caused by binding of cefdinir to all PBPs.
authors.affiliation: Department of Microbiology, Kyoto Pharmaceutical University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Hatano
authors.forename: T
authors.initials: T
authors.lastname: Nishino
mesh_terms: D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000378:metabolism; D000077525:Cefdinir; D002473:Cell Wall / Q000187:drug effects / Q000648:ultrastructure; D002511:Cephalosporins / Q000378:metabolism / Q000494:pharmacology*; D015169:Colony Count, Microbial; D006602:Hexosyltransferases; D008826:Microbial Sensitivity Tests; D008854:Microscopy, Electron; D002267:Muramoylpentapeptide Carboxypeptidase / Q000378:metabolism; D046915:Penicillin-Binding Proteins; D010406:Penicillins / Q000378:metabolism; D010458:Peptidyl Transferases; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000254:growth & development / Q000648:ultrastructure; D013297:Streptococcus pyogenes / Q000187:drug effects* / Q000254:growth & development / Q000648:ultrastructure
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D002511:Cephalosporins; D046915:Penicillin-Binding Proteins; D010406:Penicillins; D000077525:Cefdinir; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase