The reliability of Microscan conventional and rapid panels to identify Staphylococcus aureus and detect methicillin resistance: an evaluation using the tube coagulase test and mecA PCR.
Microscan (Dade Diagnostics, Brisbane) Positive Combo Type 6 (312 panels) and Rapid Positive Breakpoint Type 1 (62 panels) were evaluated for Staphylococcus aureus identification, using the tube coagulase test (TC), and oxacillin susceptibility, using mecA. A total of 374 consecutive clinical staphylococci were tested, with TC and Microscan having 100% correlation (335 identified as S. aureus and 39 as coagulase negative staphylococci by both methods). A 93% correlation was observed between Microscan and mecA PCR for oxacillin susceptibility. No very major errors (0/374 false oxacillin susceptibility) and 26 (7%) major errors (26/374 false oxacillin resistance) were found showing false resistance to oxacillin to be a problem in our population. Oxacillin Etest (AB Biodisk, Sweden) was performed on all oxacillin resistant isolates. A bimodal distribution was observed between mecA positive and negative isolates. A testing algorithm (using the Microscan panels and Etest) was developed for this laboratory to detect mecA encoded methicillin resistance. Retrospective application of this algorithm to the 374 isolates gave 100% correlation with mecA detection.
Farrell
D J
DJ
Department of Pathology, Queensland Health Pathology Services, Toowoomba Laboratory, Australia.
D001431:Bacteriological Techniques / Q000295:instrumentation*; D003030:Coagulase / Q000502:physiology; D005069:Evaluation Studies as Topic; D006801:Humans; D016106:Methicillin Resistance / Q000235:genetics; D008826:Microbial Sensitivity Tests / Q000295:instrumentation; D010068:Oxacillin / Q000494:pharmacology; D010406:Penicillins / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D013211:Staphylococcus aureus / Q000302:isolation & purification*
D003030:Coagulase; D010406:Penicillins; D010068:Oxacillin