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Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria
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Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria

Published on: May 8, 2013

Penicillin-binding proteins and cell wall composition in beta-lactam-sensitive and -resistant strains of

Yanjiao Zhou1, Aude Antignac, Shang Wei Wu

  • 1Laboratory of Microbiology, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.

Journal of Bacteriology
|November 21, 2007
PubMed

Insights

A native Staphylococcus sciuri gene, pbpD, functions similarly to the acquired Staphylococcus aureus mecA gene. Both genes confer oxacillin resistance by altering peptidoglycan biosynthesis in their respective bacterial hosts.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Genetics

Background:

  • The Staphylococcus aureus mecA gene confers methicillin resistance by encoding a penicillin-binding protein (PBP2A) with low affinity for beta-lactam antibiotics.
  • A homologous gene, pbpD, exists naturally in Staphylococcus sciuri, suggesting potential roles in antibiotic resistance or cell wall synthesis.

Purpose of the Study:

  • To investigate the function of the S. sciuri pbpD gene, a homologue of S. aureus mecA, within its native S. sciuri environment.
  • To characterize the penicillin-binding protein (PBP) patterns and peptidoglycan composition in S. sciuri strains with varying resistance profiles.

Main Methods:

  • Penicillin-binding protein (PBP) profiling using techniques like SDS-PAGE and Western blotting with specific antibodies.
  • Analysis of peptidoglycan muropeptide composition.
  • Genetic analysis of oxacillin-resistant S. sciuri isolates (SS37, K1M200, K3) and laboratory mutants.

Main Results:

  • The S. sciuri pbpD gene product, identified as PBP4, is a 84 kDa protein with low nafcillin affinity and cross-reacts with anti-S. aureus PBP2A antibodies.
  • PBP4 was overproduced in oxacillin-resistant S. sciuri strains SS37 and K1M200, with resistance attributed to the overtranscribed pbpD gene.
  • An S. aureus mecA gene conferred oxacillin resistance in S. sciuri strain K3, demonstrating functional conservation across species.

Conclusions:

  • Both S. aureus mecA and S. sciuri pbpD can act as determinants of oxacillin resistance in both S. aureus and S. sciuri.
  • The protein products, S. aureus PBP2A and S. sciuri PBP4, are involved in peptidoglycan biosynthesis.
  • The specific muropeptide composition of the peptidoglycan is influenced by the bacterial host carrying the resistance gene.

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