Prediction of mecA-positive coagulase-negative staphylococci: assessment of different phenotypic methods, breakpoints, culture media and culture conditions

J Antimicrob Chemother. 2002 Jan;49(1):197-200. doi: 10.1093/jac/49.1.197.

Abstract

Sensitivity for the detection of mecA-positive coagulase-negative staphylococci (CNS) was evaluated for different breakpoints of resistance for oxacillin using three different susceptibility tests, either on Mueller-Hinton agar supplemented with 2% NaCl (MH-NaCl agar) or on paper disc method agar supplemented with 5% defibrinated blood (PDM-blood agar). The Etest, multipoint inoculation test and disc diffusion test showed comparable sensitivity (0.96, 0.96 and 0.95, respectively) using an oxacillin breakpoint of > or = 0.5 mg/L or < or = 17 mm for the disc test, after incubation at 35 degrees C for 24 h on MH-NaCl agar. The sensitivity decreased for breakpoints > or = 1 mg/L and when PDM-blood agar was used instead of MH-NaCl agar.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins*
  • Bacteriological Techniques / methods
  • Carrier Proteins / genetics*
  • Carrier Proteins / isolation & purification
  • Coagulase / genetics*
  • Coagulase / isolation & purification
  • Culture Media / pharmacology
  • Drug Resistance, Bacterial / genetics
  • Hexosyltransferases*
  • Humans
  • Microbial Sensitivity Tests / methods
  • Microbial Sensitivity Tests / statistics & numerical data
  • Muramoylpentapeptide Carboxypeptidase / genetics*
  • Muramoylpentapeptide Carboxypeptidase / isolation & purification
  • Oxacillin / pharmacology
  • Penicillin-Binding Proteins
  • Penicillins / pharmacology
  • Peptidyl Transferases*
  • Phenotype
  • Staphylococcus / drug effects
  • Staphylococcus / genetics*
  • Staphylococcus / isolation & purification

Substances

  • Bacterial Proteins
  • Carrier Proteins
  • Coagulase
  • Culture Media
  • Penicillin-Binding Proteins
  • Penicillins
  • Peptidyl Transferases
  • Hexosyltransferases
  • Muramoylpentapeptide Carboxypeptidase
  • Oxacillin