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Evaluation of the LightCycler Methicillin-Resistant Staphylococcus aureus (MRSA) Advanced Test for Detection of MRSA Nasal Colonization
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| Zeitschriftentitel: | Journal of Clinical Microbiology |
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| Personen und Körperschaften: | , , , , , , , , , |
| In: | Journal of Clinical Microbiology, 51, 2013, 9, S. 2869-2874 |
| Format: | E-Article |
| Sprache: | Englisch |
| veröffentlicht: |
American Society for Microbiology
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| Schlagwörter: |
| Zusammenfassung: | <jats:title>ABSTRACT</jats:title> <jats:p> Rapid detection of methicillin-resistant <jats:named-content content-type="genus-species">Staphylococcus aureus</jats:named-content> (MRSA) nasal colonization is crucial for the prevention and control of MRSA infections in health care settings. The LightCycler MRSA Advanced Test (Roche Diagnostics) is a commercially available real-time PCR assay for direct detection of MRSA nasal colonization by targeting of the staphylococcal cassette chromosome <jats:italic>mec</jats:italic> (SCC <jats:italic>mec</jats:italic> )- <jats:italic>orfX</jats:italic> junction. The diagnostic performance of the assay was compared with that of ChromID MRSA agar (bioMérieux) culture and an in-house duplex real-time PCR assay. Among 1,246 nasal swab specimens collected from 2 general hospitals in Hong Kong, 174 (14%) were considered true positive for MRSA. Chromogenic culture and the in-house real-time PCR assay identified 147 (84.5%) and 133 (76.4%) true-positive cases with specificities of 100% and 98.6%, respectively. Based on the target melting temperature ( <jats:italic> T <jats:sub>m</jats:sub> </jats:italic> ) values (57.0 to 62.0°C) defined by the manufacturer, the LightCycler MRSA Advanced Test identified only 85 (48.9%) true-positive specimens. Interestingly, an additional 60 (34.5%) true-positive specimens were detected despite atypical <jats:italic> T <jats:sub>m</jats:sub> </jats:italic> values of 55°C, providing overall sensitivity and specificity values of 83.3% and 99%, respectively. Among isolates with <jats:italic> T <jats:sub>m</jats:sub> </jats:italic> values of 55°C, most were typed as clonal complex 45 (CC45). By sequence analysis of the SCC <jats:italic>mec-orfX</jats:italic> junction, characteristic single-nucleotide polymorphisms (SNPs) were identified only in isolates with <jats:italic> T <jats:sub>m</jats:sub> </jats:italic> values of 55°C and not in those with typical <jats:italic> T <jats:sub>m</jats:sub> </jats:italic> values. It is conceivable that those SNPs were located inside the target region of the proprietary hybridization probes, which resulted in a <jats:italic> T <jats:sub>m</jats:sub> </jats:italic> shift in the melting curve analysis. Our study highlights the importance of a global evaluation of commercial kits so that the interpretation algorithm covers different lineages of MRSA clones prevalent in various geographical regions. </jats:p> |
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| Umfang: | 2869-2874 |
| ISSN: |
0095-1137
1098-660X |
| DOI: | 10.1128/jcm.00488-13 |