title: Validation of the MicroScan-96 for the species identification and methicillin susceptibility testing of clinical significant coagulase-negative staphylococci.
abstract: An automated system, MicroScan WalkAway-96, in conjugation with Combo Pos® 28 panels, was validated for the identification and methicillin susceptibility of coagulase-negative staphylococci (CNS). The performance of this system was evaluated on 428 CNS. Identification results were compared using a validated in-house method. Methicillin susceptibility was compared with oxacillin MIC testing and the presence of the mecA gene by PCR (in-house real-time method). The MicroScan system correctly identified 94.6% of the staphylococci (405 out of 428). 3.5% of the strains (15 out of 428) were not correctly identified. 1.9% of the isolates (8 out of 428) were correctly identified with a low probability. Identification of Staphylococcus warneri and Staphylococcus lugdunensis was determined with the least accuracy. Microscan combines both oxacillin and cefoxitin for determination of the methicillin susceptibility result. Correlation between this result and the mecA method was 97.6%. Correlation with the oxacillin MIC method was also 97.6%. Fourteen isolates showed a discrepant result, 8 were reported to be resistant in mecA-negative strains, 2 were reported false-susceptible in mecA positive strains and 4 strains showed a discrepant result with oxacillin MIC, but not with mecA determination. The automated system can be considered a simple and reliable method for identification and methicillin susceptibility of CNS.
authors.affiliation: Laboratory of Medical Microbiology, University Hospital Antwerp, Wilrijkstraat 10, Edegem, Belgium. lisbethpatteet@hotmail.com
authors.forename: L
authors.initials: L
authors.lastname: Patteet
authors.forename: H
authors.initials: H
authors.lastname: Goossens
authors.forename: M
authors.initials: M
authors.lastname: Ieven
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001331:Automation / Q000379:methods; D001431:Bacteriological Techniques / Q000379:methods*; D003030:Coagulase / Q000378:metabolism*; D003951:Diagnostic Errors / Q000706:statistics & numerical data; D005798:Genes, Bacterial; D006801:Humans; D008712:Methicillin / Q000494:pharmacology; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D013203:Staphylococcal Infections / Q000175:diagnosis* / Q000382:microbiology*; D013210:Staphylococcus / Q000145:classification* / Q000187:drug effects / Q000201:enzymology / Q000302:isolation & purification*
chemical_list: D000900:Anti-Bacterial Agents; D003030:Coagulase; D008712:Methicillin