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Genotyping of Staphylococcus aureus by Ribosomal Spacer PCR (RS-PCR)
08:51

Genotyping of Staphylococcus aureus by Ribosomal Spacer PCR (RS-PCR)

Published on: November 4, 2016

Occurrence of protein a in staphylococcal strains: quantitative aspects and correlation to antigenic and

G Kronvall1, J H Dossett, P G Quie

  • 1Department of Medicine, University of New Mexico, Albuquerque, New Mexico 87106.

Infection and Immunity
|January 1, 1971
PubMed

Insights

Staphylococcus aureus protein A is present in 90% of strains, aiding in bacterial identification. Production is influenced by incubation temperature and salt concentration, but not by storage or antigenic traits.

Area of Science:

  • Microbiology
  • Immunology
  • Bacterial Pathogenesis

Background:

  • Protein A is a surface protein found in Staphylococcus aureus.
  • Its presence can be detected using specific binding assays.

Purpose of the Study:

  • To determine the prevalence of Protein A in Staphylococcus aureus strains.
  • To investigate factors influencing Protein A production and detection.

Main Methods:

  • Radioactively labeled myeloma globulin was used to detect Protein A on intact bacteria.
  • Strains of S. aureus and S. epidermidis were tested.
  • Production was assessed under varying incubation temperatures, times, inoculum sizes, and salt concentrations.
  • Formalin treatment and cold storage effects were evaluated.
  • Correlation with phage typing and antigenic characteristics was examined.

Main Results:

  • 90% of Staphylococcus aureus strains (141/156) possessed Protein A.
  • No S. epidermidis strains (0/47) were positive for Protein A.
  • Protein A production was significantly affected by incubation temperature and high NaCl concentration (90% suppression).
  • Formalin treatment reduced detected Protein A, with no further reduction upon cold storage.
  • No correlation was found between Protein A presence/absence and phage type, phage group, or previously described antigenic characteristics.

Conclusions:

  • Protein A is a highly prevalent marker in Staphylococcus aureus, distinguishing it from S. epidermidis.
  • Environmental factors like temperature and salinity critically influence Protein A expression.
  • Protein A detection is a reliable method for S. aureus identification, independent of phage typing or specific antigenic profiles.

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