title: Detection of methicillin-resistant Staphylococcus aureus (MRSA) from growth on mannitol salt oxacillin agar using PCR for nosocomial surveillance.
abstract: This study evaluated a polymerase chain reaction (PCR) method for detection of methicillin-resistant Staphylococcus aureus (MRSA) in specimens referred for nosocomial surveillance. PCR was used to detect the mecA and nuc gene targets using yellow growth on mannitol salt agar containing 6 mg/liter oxacillin (MSO-6) as a source of DNA (N = 645). The diagnostic values for PCR compared with culture methods were 97% specificity, 100% sensitivity, 96% positive predictive value, and 100% negative predictive value. Total cost for PCR per test is $3.62 compared to $4.77 for culture. However, the total cost per specimen is significantly lower due to only 20% of all surveillance specimens producing yellow colonies on MSO-6. The average turnaround time for the PCR method is 48 h compared with 82 h for culture. PCR amplification of mecA and nuc genes using yellow colonies on MSO-6 is a simple, fast, accurate and cost-effective method for routine use in clinical laboratories for detecting MRSA in surveillance specimens.
authors.affiliation: Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Jayaratne
authors.forename: C
authors.initials: C
authors.lastname: Rutherford
mesh_terms: D000362:Agar; D001426:Bacterial Proteins / Q000235:genetics*; D001431:Bacteriological Techniques / Q000191:economics; D002352:Carrier Proteins / Q000235:genetics; D003428:Cross Infection / Q000382:microbiology*; D003470:Culture Media; D004720:Endonucleases; D006602:Hexosyltransferases; D006801:Humans; D008353:Mannitol; D016106:Methicillin Resistance / Q000235:genetics*; D008836:Micrococcal Nuclease; D002267:Muramoylpentapeptide Carboxypeptidase / Q000235:genetics; D010068:Oxacillin; D046915:Penicillin-Binding Proteins; D010406:Penicillins; D010458:Peptidyl Transferases; D016133:Polymerase Chain Reaction / Q000191:economics / Q000379:methods*; D012680:Sensitivity and Specificity; D013203:Staphylococcal Infections / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification*
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D003470:Culture Media; D046915:Penicillin-Binding Proteins; D010406:Penicillins; C074002:nuc protein, staphylococcus; D008353:Mannitol; D000362:Agar; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D004720:Endonucleases; D008836:Micrococcal Nuclease; D002267:Muramoylpentapeptide Carboxypeptidase; D010068:Oxacillin