| Summary: | <p>Abstract</p> <p>Background</p> <p>The bacterium <it>Staphylococcus aureus</it> constitutes one of the most important causes of nosocomial infections. One out of every three individuals naturally carries <it>S. aureus</it> in their anterior nares, and nasal carriage is associated with a significantly higher infection rate in hospital settings. Nasal carriage can be either persistent or intermittent, and it is the persistent carriers who, as a group, are at the highest risk of infection and who have the highest nasal <it>S. aureus</it> cell counts. Prophylactic decolonization of <it>S. aureus</it> from patients’ noses is known to reduce the incidence of postsurgical infections, and there is a clear rationale for rapid identification of nasal <it>S. aureus</it> carriers among hospital patients.</p> <p>Findings</p> <p>A molecular diagnostic assay was developed which is based on helicase-dependent target amplification and amplicon detection by chip hybridization to a chip surface, producing a visible readout. Nasal swabs from 70 subjects were used to compare the molecular assay against culturing on “CHROMagar Staph aureus” agar plates. The overall relative sensitivity was 89%, and the relative specificity was 94%. The sensitivity rose to 100% when excluding low-count subjects (<100 <it>S. aureus</it> colony-forming units per swab).</p> <p>Conclusions</p> <p>This molecular assay is much faster than direct culture and has sensitivity that is appropriate for identification of high-count (>100 <it>S. aureus</it> colony-forming units per swab) nasal <it>S. aureus</it> carriers who are at greatest risk for nosocomial infections.</p>
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