Association between Type A blaZ Gene Polymorphism and Cefazolin Inoculum Effect in Methicillin-Susceptible Staphylococcus aureus

Antimicrob Agents Chemother. 2016 Oct 21;60(11):6928-6932. doi: 10.1128/AAC.01517-16. Print 2016 Nov.

Abstract

Some proportion of type A blaZ gene-positive methicillin-susceptible Staphylococcus aureus strains exhibit the cefazolin inoculum effect (CIE). The type A blaZ gene was divided into two groups by single nucleotide polymorphisms (SNPs) at Ser226Pro and Cys229Tyr. The median cefazolin MICs at a high inoculum concentration were 5.69 μg/ml for the Ser-Cys group and 40.32 μg/ml for the Pro-Tyr group (P = 0.01). The SNPs at codons 226 and 229 in the amino acid sequence encoded by the blaZ gene were closely associated with the CIE.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Bacterial Proteins / genetics*
  • Cefazolin / pharmacology*
  • Cysteine / genetics
  • Dipeptides / genetics
  • Humans
  • Methicillin / pharmacology
  • Microbial Sensitivity Tests
  • Phylogeny
  • Polymorphism, Single Nucleotide*
  • Serine / genetics
  • Staphylococcus aureus / drug effects*
  • Staphylococcus aureus / genetics*
  • Staphylococcus aureus / isolation & purification

Substances

  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Dipeptides
  • prolyl-tyrosine
  • Serine
  • Cefazolin
  • Cysteine
  • Methicillin