Details

Autor(en) / Beteiligte

• Roisin, S.
• Laurent, C.
• Nonhoff, C.
• Deplano, A.
• Hallin, M.
• Byl, B.
• Struelens, M. J.
• Denis, O.

Titel

Positive predictive value of the Xpert MRSA assay diagnostic for universal patient screening at hospital admission: influence of the local ecology

Ist Teil von

• European journal of clinical microbiology & infectious diseases, 2012-05, Vol.31 (5), p.873-880

Ort / Verlag

Berlin/Heidelberg: Springer-Verlag

Erscheinungsjahr

2012

Quelle

MEDLINE

Beschreibungen/Notizen

• The purpose of this study was to assess the accuracy of the Xpert MRSA assay (XP) for the detection of methicillin-resistant Staphylococcus aureus (MRSA) carriage upon hospital admission. Nasal swabs were prospectively collected for MRSA screening from 1,891 patients admitted to a teaching hospital. XP results were compared to chromogenic agar culture results. MRSA was cultured in 61 specimens (3%). Compared with culture, XP had a sensitivity, specificity, positive, and negative predictive value of 60.7, 97.3, 37.8, and 98.9%, respectively. The median turnaround time (TAT) for the results was 3 h. Of 24 MRSA isolated from XP-negative samples, three harbored composite SCC mec . Among 61 samples with culture-negative but XP-positive results, 15 methicillin-susceptible S. aureus (MSSA) isolates tested positive by XP on pure colony lysates. These MSSA included: (i) strains with SCC mec deletion encompassing mecA and (ii) multilocus sequence typing (MLST) clonal complex (CC) 1 strains harboring a chromosomal sequence homologous to one of the orfX –SCC mec junction sequences targeted by XP. On account of the low sensitivity and positive predictive value in a hospital patient population with moderate prevalence of MRSA, culture still appears to be necessary in order to confirm polymerase chain reaction (PCR) results. The emergence of new SCC mec variants and the presence of MSSA harboring cross-reactive SCC mec -like elements may challenge the successful implementation of such detection systems.