A highly vancomycin-resistant laboratory mutant of Staphylococcus aureus. Academic Article uri icon

Overview

abstract

  • A resistant mutant with vancomycin MIC of 100 micrograms/ml was isolated relatively easily through step pressure in the laboratory from a Staphylococcus aureus strain with initial MIC of 1.5 micrograms/ml for the antibiotic. Upon addition of vancomycin (50 micrograms/ml) to the growth medium mass increase of the culture and peptidoglycan synthesis continued but cell division (daughter cell separation), cell wall turnover and autolysis were inhibited, resulting in the production of multicellular clumps of bacteria. Parallel with the increase of culture density, the concentration of vancomycin measured both by biological activity and by HPLC gradually declined in the culture medium. Cell division and wall turnover of the culture resumed with the production of cells of normal morphology at the time when the concentration of the drug in the medium decreased below 0.5-1.0 micrograms/ml. There was no detectable change in the antibiotic concentration in the culture medium during growth of a vancomycin-resistant (vanA-positive) strain of Enterococcus faecium and an intrinsically vancomycin-resistant strain of Leuconostoc. The vancomycin-resistant staphylococcal mutant gave no signal with the vanA or vanB DNA probes and contained no detectable D-lactate terminating cell wall precursors. The biochemical mechanism and clinical significance of such glycopeptide-resistant mutants remained to be established.

publication date

  • September 1, 1996

Research

keywords

  • Anti-Bacterial Agents
  • Carbon-Oxygen Ligases
  • Staphylococcus aureus
  • Vancomycin

Identity

Scopus Document Identifier

  • 0030246884

Digital Object Identifier (DOI)

  • 10.1111/j.1574-6968.1996.tb08424.x

PubMed ID

  • 8810499

Additional Document Info

volume

  • 142

issue

  • 2-3