Faculty Collaboration Database

Comparison of the next-generation Xpert MRSA/SA BC assay and the GeneOhm StaphSR assay to routine culture for identification of Staphylococcus aureus and methicillin-resistant S. aureus in positive-blood-culture broths. J Clin Microbiol 2015 Mar;53(3):804-9

Date

12/30/2014

Pubmed ID

25540397

Pubmed Central ID

PMC4390651

DOI

10.1128/JCM.03108-14

Scopus ID

2-s2.0-84923351710 (requires institutional sign-in at Scopus site)   62 Citations

Abstract

A bloodstream infection with Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA), is a serious condition that carries a high mortality rate and is also associated with significant hospital costs. The rapid and accurate identification and differentiation of methicillin-susceptible S. aureus (MSSA) and MRSA directly from positive blood cultures has demonstrated benefits in both patient outcome and cost-of-care metrics. We compare the next-generation Xpert MRSA/SA BC (Xpert) assay to the GeneOhm StaphSR (GeneOhm) assay for the identification and detection of S. aureus and methicillin resistance in prospectively collected blood culture broths containing Gram-positive cocci. All results were compared to routine bacterial culture as the gold standard. Across 8 collection and test sites, the Xpert assay demonstrated a sensitivity of 99.6% (range, 96.4% to 100%) and a specificity of 99.5% (range, 98.0% to 100%) for identifying S. aureus, as well as a sensitivity of 98.1% (range, 87.5% to 100%) and a specificity of 99.6% (range, 98.3% to 100%) for identifying MRSA. In comparison, the GeneOhm assay demonstrated a sensitivity of 99.2% (range, 95.2% to 100%) and a specificity of 96.5% (range, 89.2% to 100%) for identifying S. aureus, as well as a sensitivity of 94.3% (range, 87.5% to 100%) and a specificity of 97.8% (range, 96.1% to 100%) for identifying MRSA. Five of six cultures falsely reported as negative for MRSA by the GeneOhm assay were correctly identified as positive by the Xpert assay, while one culture falsely reported as negative for MRSA by the Xpert assay was correctly reported as positive by the GeneOhm assay.

Author List

Buchan BW, Allen S, Burnham CA, McElvania TeKippe E, Davis T, Levi M, Mayne D, Pancholi P, Relich RF, Thomson R, Ledeboer NA

Authors

Blake W. Buchan PhD Professor in the Pathology department at Medical College of Wisconsin
Nathan A. Ledeboer PhD Chief, Professor in the Pathology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Adolescent
Adult
Bacteremia
Bacteriological Techniques
Blood
Child
Child, Preschool
Humans
Infant
Methicillin Resistance
Molecular Diagnostic Techniques
Prospective Studies
Sensitivity and Specificity
Staphylococcal Infections
Staphylococcus aureus