Staph ID/R: A rapid method for determining Staphylococcus species identity and detecting the mecA gene directly from positive blood culture

Chris Pasko, Brian Hicke*, John Dunn, Heidi Jaeckel, Dan Nieuwlandt, Diane Weed, Evelyn Woodruff, Xiaotian Zheng, Robert Jenison

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Rapid diagnosis of staphylococcal bacteremia directs appropriate antimicrobial therapy, leading to improved patient outcome. We describe herein a rapid test (<75 min) that can identify the major pathogenic strains of Staphylococcus to the species level as well as the presence or absence of the methicillin resistance determinant gene, mecA. The test, Staph ID/R, combines a rapid isothermal nucleic acid amplification method, helicase-dependent amplification (HDA), with a chip-based array that produces unambiguous visible results. The analytic sensitivity was 1 CFU per reaction for the mecA gene and was 1 to 250 CFU per reaction depending on the staphylococcal species present in the positive blood culture. Staph ID/R has excellent specificity as well, with no cross-reactivity observed. We validated the performance of Staph ID/R by testing 104 frozen clinical positive blood cultures and comparing the results with rpoB gene or 16S rRNA gene sequencing for species identity determinations and mecA gene PCR to confirm mecA gene results. Staph ID/R agreed with mecA gene PCR for all samples and agreed with rpoB/16S rRNA gene sequencing in all cases except for one sample that contained a mixture of two staphylococcal species, one of which Staph ID/R correctly identified, for an overall agreement of 99.0% (P < 0.01). Staph ID/R could potentially be used to positively affect patient management for Staphylococcus-mediated bacteremia.

Original languageEnglish (US)
Pages (from-to)810-817
Number of pages8
JournalJournal of clinical microbiology
Volume50
Issue number3
DOIs
StatePublished - Mar 2012

ASJC Scopus subject areas

  • Microbiology (medical)

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