[Comparison of different phenotypic methods with polymerase chain reaction (PCR) for the detection of resistance to oxacillin in coagulase negative staphylococci].
The mecA gene which confers the oxacillin resistance has been searched by PCR in 290 (124 positives, 166 negatives) coagulase-negative staphylococci (CNS) belonging to twelve species. The results were compared with the oxacillin MIC values obtained by agar dilution (4% NaCl) or by the ATB STAPH method (Api-bioMérieux; 0%, 2%, 5% NaCl) and growth inhibitory diameters obtained by agar diffusion with an oxacillin disk placed at 30 degrees C without NaCl, or at 35 degrees C in presence of 2% or 5% NaCl. Sensitivity of oxacillin resistance detection depends upon the salt concentration and the method used. The optimum concentration is 2%. With this concentration, the Api ATB test appears as the more performant (sensitivity: 89.8%). Search for the mecA gene by PCR represents a very interesting method that detects 96.9% of the oxacillin-resistant CNS strains.
Zambardi
G
G
Département d'Etudes et de Recherche en Bactériologie (EA 1655), Faculté de Médecine Alexis-Carrel, Lyon, France.
Lecoq
M
M
Reverdy
M E
ME
Bes
M
M
Freney
J
J
Fleurette
J
J
D001431:Bacteriological Techniques; D003030:Coagulase / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004352:Drug Resistance, Microbial; D006801:Humans; D066298:In Vitro Techniques; D010068:Oxacillin / Q000494:pharmacology*; D010406:Penicillins / Q000494:pharmacology; D016133:Polymerase Chain Reaction / Q000379:methods*; D013210:Staphylococcus / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*
D003030:Coagulase; D010406:Penicillins; D010068:Oxacillin
Comparaison de différentes méthodes phénotypiques avec la réaction de polymérisation en chaîne (PCR) pour la détection de la résistance à l'oxacilline chez les staphylocoques à coagulase-négative.