A selective broth enrichment combined with real-time nuc-mecA-PCR in the exclusion of MRSA.
We analyzed the performance of a selective enrichment broth combined with Taqman-based real-time duplex nuc-mecA-PCR to expedite the screening of methicillin-resistant Staphylococcus aureus (MRSA). We found the broth to be able to select MRSA strains (oxacillin MIC range 4-256 microg/ml) from MSSA strains. A total of 31 MRSA strains were found from 1250 clinical samples screened. The nuc-mecA-PCR was positive from all enrichment broths containing MRSA. From the remaining 1219 samples negative for MRSA on culture/subculture, 138 samples were nuc+/mecA+ in PCR. The sensitivity of the test was 93.5%, specificity 88.6%, positive predictive value 17.3%, and negative predictive value 99.8% as compared to culture. Thus, with this method, the negative MRSA results can be reliably reported within 24-48 h from sampling. The method is a practical additional alternative to those already described for the same purpose.
Pasanen
Tanja
T
Division of Clinical Microbiology, HUSLAB, Helsinki University Hospital, Helsinki, Finland.
Korkeila
Maija
M
Mero
Sointu
S
Tarkka
Eveliina
E
Piiparinen
Heli
H
Vuopio-Varkila
Jaana
J
Vaara
Martti
M
Tissari
Päivi
P
D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics*; D018929:Cell Culture Techniques / Q000379:methods*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000235:genetics / Q000302:isolation & purification*; D008836:Micrococcal Nuclease / Q000737:chemistry / Q000235:genetics*; D046915:Penicillin-Binding Proteins; D016133:Polymerase Chain Reaction / Q000379:methods*; D013203:Staphylococcal Infections / Q000175:diagnosis / Q000382:microbiology*
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D046915:Penicillin-Binding Proteins; C487789:mecA protein, Staphylococcus aureus; C074002:nuc protein, staphylococcus; D008836:Micrococcal Nuclease