title: Direct detection of nasal Staphylococcus aureus carriage via helicase-dependent isothermal amplification and chip hybridization.
abstract: BACKGROUND
  The bacterium Staphylococcus aureus constitutes one of the most important causes of nosocomial infections. One out of every three individuals naturally carries S. aureus 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 S. aureus cell counts. Prophylactic decolonization of S. aureus from patients' noses is known to reduce the incidence of postsurgical infections, and there is a clear rationale for rapid identification of nasal S. aureus carriers among hospital patients.
  
  
  RESULTS
  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 S. aureus colony-forming units per swab).
  
  
  CONCLUSIONS
  This molecular assay is much faster than direct culture and has sensitivity that is appropriate for identification of high-count (>100 S. aureus colony-forming units per swab) nasal S. aureus carriers who are at greatest risk for nosocomial infections.
authors.affiliation: Great Basin Corporation, 2441 South 3850 West, Salt Lake City, UT 84120, USA.
authors.forename: Georges C
authors.initials: GC
authors.lastname: Frech
authors.forename: Denton
authors.initials: D
authors.lastname: Munns
authors.forename: Robert D
authors.initials: RD
authors.lastname: Jenison
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Hicke
mesh_terms: D001483:Base Sequence; D002353:Carrier State; D017931:DNA Primers; D004269:DNA, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D006801:Humans; D009296:Nasal Cavity / Q000382:microbiology*; D009693:Nucleic Acid Hybridization; D012680:Sensitivity and Specificity; D013203:Staphylococcal Infections / Q000175:diagnosis / Q000382:microbiology; D013211:Staphylococcus aureus / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D017931:DNA Primers; D004269:DNA, Bacterial