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Molecular characterization of a mutation affecting the amount of Streptococcus pneumoniae penicillin-binding protein

L Selakovitch-Chenu1, P Giammarinaro, M Sicard

  • 1Laboratoire de Microbiologie et Génétique Moléculaire du CNRS, Toulouse, France.

Microbial Drug Resistance (Larchmont, N.Y.)
|October 1, 1997
PubMed

Insights

A single base-pair deletion in the Streptococcus pneumoniae PBP3 gene

Area of Science:

  • Microbiology
  • Molecular Biology
  • Genetics

Background:

  • Streptococcus pneumoniae penicillin-binding protein 3 (PBP3) is crucial for cell wall synthesis.
  • Understanding PBP3 regulation is key to developing effective antibiotic resistance strategies.

Purpose of the Study:

  • To investigate the molecular basis of reduced PBP3 expression in a laboratory mutant of Streptococcus pneumoniae.
  • To determine the impact of genetic alterations in the PBP3 gene on cefotaxime resistance.

Main Methods:

  • Sequencing of the PBP3 gene (dacA) and its upstream regulatory regions in wild-type and mutant strains.
  • Analysis of PBP3 protein levels using PBP gels.
  • Phenotypic analysis of cefotaxime resistance.

Main Results:

  • A one base-pair deletion was identified in the upstream sequence of the PBP3 gene in the laboratory mutant.
  • This deletion was shown to decrease the amount of PBP3 protein produced.
  • The mutation conferred altered cefotaxime resistance when transferred into resistant strains.

Conclusions:

  • A specific upstream deletion in the PBP3 gene is responsible for reduced PBP3 levels and affects cefotaxime resistance in Streptococcus pneumoniae.
  • This finding provides insight into the genetic mechanisms of antibiotic resistance in S. pneumoniae.

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