Open AccessPossible physiological functions of penicillin-binding proteins in Staphylococcus aureus
Author(s) -
Nafsika H. Georgopapadakou,
B A Dix,
Yolanda Mauriz
Publication year - 1986
Publication title -
antimicrobial agents and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.07
H-Index - 259
eISSN - 1070-6283
pISSN - 0066-4804
DOI - 10.1128/aac.29.2.333
Subject(s) - penicillin binding proteins , staphylococcus aureus , cefotaxime , peptidoglycan , microbiology and biotechnology , biology , penicillin , cell wall , antibiotics , lysis , antibacterial agent , biochemistry , bacteria , genetics
There are four penicillin-binding proteins (PBPs) in Staphylococcus aureus, of which PBPs 2 and 3 are essential. Cefotaxime binds selectively to PBP 2, and cephalexin binds to PBP 3, each at its respective MIC. The morphology of S. aureus strains grown in the presence of the two antibiotics was examined by phase-contrast and scanning electron microscopy. Exposure of the cells to cefotaxime at concentrations at which it bound selectively to PBP 2 resulted in the extrusion of cytoplasm and cell lysis, whereas exposure to cephalexin at concentrations at which it bound exclusively to PBP 3 resulted in cell enlargement and the cessation of septation. The latter morphological response was very similar to that produced by norfloxacin. The results suggest that in S. aureus, PBP 2 may be the primary peptidoglycan transpeptidase, and PBP 3 may be involved in septation.