This Article Full Text Full Text (PDF) Other Versions of this Article: JCM.00552-07v1 45/7/2191    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Stamper, P. D. Articles by Carroll, K. C. Search for Related Content PubMed PubMed Citation Articles by Stamper, P. D. Articles by Carroll, K. C.

 Previous Article  |  Next Article 

Journal of Clinical Microbiology, July 2007, p. 2191-2196, Vol. 45, No. 7
0095-1137/07/$08.00+0     doi:10.1128/JCM.00552-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

Clinical Validation of the Molecular BD GeneOhm StaphSR Assay for Direct Detection of Staphylococcus aureus and Methicillin-Resistant Staphylococcus aureus in Positive Blood Cultures

Division of Medical Microbiology, Department of Pathology, Johns Hopkins University School of Medicine,¹ Microbiology Laboratory, Johns Hopkins Hospital, Baltimore, Maryland²

Received 12 March 2007/ Returned for modification 19 April 2007/ Accepted 14 May 2007

The rapid detection of Staphylococcus aureus bacteremia and a swift determination of methicillin susceptibility has serious clinical implications affecting patient mortality. This study evaluated the StaphSR assay (BD GeneOhm, San Diego, CA), a real-time PCR assay, for the identification and differentiation of methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) from 300 positive blood cultures. The BD GeneOhm StaphSR assay was performed and interpreted according to the manufacturer's recommendations. Positive blood cultures (containing predominantly gram-positive cocci in clusters) were subcultured on 5% sheep blood agar plates. After 18 to 24 h of incubation, isolates morphologically consistent with S. aureus were presumptively identified by latex agglutination (Staphaurex Plus; Remel, Lenexa, KS). Susceptibility testing was initially performed with the Phoenix automated microbiology system (BD Diagnostics, Sparks, MD). Additional susceptibility testing of samples with discrepant results was done using BBL oxacillin screen agar (BD Diagnostics, Sparks, MD), oxacillin and cefoxitin Etests (AB Biodisk, Solna, Sweden) on Mueller-Hinton agar, an immunoassay for penicillin binding protein 2' (Denka Seiken Co., Tokyo, Japan), and mecA PCR. The sensitivity, specificity, and positive and negative predictive values of the BD GeneOhm StaphSR assay for MSSA detection were 98.9, 96.7, 93.6, and 99.5%, respectively. For the detection of MRSA, the BD GeneOhm StaphSR assay was 100% sensitive and 98.4% specific; positive and negative predictive values for MRSA detection were 92.6 and 100%, respectively. Inhibition was seen with only one sample, and the issue was resolved upon retesting. The BD GeneOhm StaphSR assay appears to be a valuable diagnostic tool for quickly differentiating bacteremia caused by MSSA and MRSA from that caused by other gram-positive cocci.

Published ahead of print on 23 May 2007.

This article has been cited by other articles:

• Ruimy, R., Dos-Santos, M., Raskine, L., Bert, F., Masson, R., Elbaz, S., Bonnal, C., Lucet, J.-C., Lefort, A., Fantin, B., Wolff, M., Hornstein, M., Andremont, A. (2008). Accuracy and Potential Usefulness of Triplex Real-Time PCR for Improving Antibiotic Treatment of Patients with Blood Cultures Showing Clustered Gram-Positive Cocci on Direct Smears. J. Clin. Microbiol. 46: 2045-2051 [Abstract] [Full Text]