Laboratory diagnosis of oxacillin resistance in Staphylococcus aureus by a multiplex-polymerase chain reaction assay.
A polymerase chain reaction (PCR) test was developed in which the mecA gene responsible for the intrinsic resistance to oxacillin in Staphylococcus aureus and the gyrA gene, always present in this species, were amplified in one operation. Among the 468 clinical isolates tested, the results obtained for 454 of the isolates (97%) were consistent with those of MIC determination. Discrepant results were noted for strains with low-level oxacillin resistance (MICs, 4-8 micrograms/ml) and mecA gene negative. For these strains, susceptibility to oxacillin was restored in the presence of a beta-lactamase inhibitor, which suggested a resistance by penicillinase hyperproduction. In contrast, all of the high-level resistant strains (MICs, > 8 micrograms/ml) carried the mecA gene. The presence of this gene has frequently been associated with resistance to gentamicin, tetracycline, erythromycin, lincomycin, and pefloxacin. The PCR assay described in this study can be accomplished with ease and total confidence in the clinical microbiologic laboratory for a rapid and effective establishment of antistaphylococcal chemotherapy.
Department of Studies and Research of Medical Bacteriology, Alexis Carrel Faculty of Medicine, Lyons, France.
G
G
Zambardi
M E
ME
Reverdy
S
S
Bland
M
M
Bes
J
J
Freney
J
J
Fleurette
D001426:Bacterial Proteins / Q000235:genetics; D001434:Bacteriophage Typing; D027081:DNA Gyrase; D004250:DNA Topoisomerases, Type II / Q000235:genetics; D004347:Drug Interactions; D005798:Genes, Bacterial / Q000235:genetics; D008826:Microbial Sensitivity Tests; D010068:Oxacillin / Q000494:pharmacology*; D010403:Penicillin Resistance / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012965:Sodium Chloride / Q000494:pharmacology; D013211:Staphylococcus aureus / Q000187:drug effects / Q000235:genetics*; D013407:Sulbactam / Q000494:pharmacology
D001426:Bacterial Proteins; D012965:Sodium Chloride; D027081:DNA Gyrase; D004250:DNA Topoisomerases, Type II; D013407:Sulbactam; D010068:Oxacillin