Studies on the mechanism of intrinsic resistance to beta-lactam antibiotics in group D streptococci. Academic Article uri icon

Overview

abstract

  • Six penicillin-binding proteins (PBPs) were detected in clinical isolates of each one of three group D streptococci: Streptococcus bovis, S. faecalis and S. faecium. When examined in whole organisms, the PBPs of S. faecium, the most penicillin-resistant species of group D streptococci, generally had lower affinities for the antibiotic than those of S. faecalis (intermediate penicillin resistance), which in turn were of lower affinity than those of S. bovis (penicillin-sensitive). On the other hand, no quantitative correlation could be established between the binding of penicillin to any one PBP or group of PBPs, and the penicillin MIC value for the corresponding micro-organism. Examination of the amounts of antibiotic bound and the rates of binding to PBPs of equal numbers of protoplasts and whole bacteria of S. faecalis and S. faecium, indicated that there was no permeability barrier to benzylpenicillin in the cell walls of these species. The lower antibacterial effectiveness of cephalothin compared with ampicillin in group D streptococci was paralleled by the higher concentrations of cephalothin needed in competition assays to inhibit the lower molecular size PBPs of these bacteria.

publication date

  • March 1, 1983

Research

keywords

  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Hexosyltransferases
  • Muramoylpentapeptide Carboxypeptidase
  • Peptidyl Transferases
  • Streptococcus

Identity

Scopus Document Identifier

  • 0020656855

Digital Object Identifier (DOI)

  • 10.1099/00221287-129-3-813

PubMed ID

  • 6409985

Additional Document Info

volume

  • 129

issue

  • 3