Clinical and laboratory features of invasive community-onset methicillin-resistant Staphylococcus aureus infection: a prospective case–control study

  • M. C. Wehrhahn
  • J. O. Robinson
  • J. C. Pearson
  • F. G. O’Brien
  • H. L. Tan
  • G. W. Coombs
  • E. M. Pascoe
  • R. Lee
  • P. Salvaris
  • R. Salvaris
  • D. New
  • R. J. Murray


Differences between the features of invasive community-onset methicillin-resistant Staphylococcus aureus (cMRSA) and methicillin-susceptible S. aureus (cMSSA) infections are incompletely understood. Fifty-seven patients with invasive cMRSA infection were prospectively identified at two teaching hospitals; for each cMRSA case, two cases of invasive cMSSA infection acted as controls. The primary outcome was 30-day all-cause mortality. Patients with invasive cMRSA infection were more likely to be Aboriginal (25% vs. 14%, age-adjusted odds ratio [OR] 2.5, p = 0.037), reside in a long-term care facility and/or have been hospitalised in the previous year (51% vs. 34%, p = 0.04) and less likely to have endocarditis (2% vs. 12%, p = 0.02) or require admission to an intensive care unit or high-dependency area (7% vs. 21%, p = 0.02). All-cause mortality at 30 days was similar in the cMRSA and cMSSA groups (9% vs. 7%, p = 0.68). Panton–Valentine leukocidin (PVL) genes were detected in a similar proportion of cMRSA and cMSSA isolates (32% vs. 27%, p = 0.49) and the presence of PVL genes was associated with younger age (35 years vs. 55 years, p < 0.001), Aboriginal ethnicity (38% vs. 10%, p < 0.001), skin and soft-tissue infection (54% vs. 19%, p < 0.001), lower illness severity at presentation (SAPS II score 9 vs. 21, p = 0.001) and shorter hospitalisation (9 days vs. 24 days, p < 0.001). Patients with “PVL-positive” and “PVL-negative” S. aureus infection had similar 30-day all-cause mortality (4% vs. 9%, p = 0.28). Few clinical features differentiated patients with invasive cMRSA infection from those with infection caused by cMSSA. Invasive “PVL-positive” S. aureus infection was associated with less morbidity but similar mortality to “PVL-negative” infection.



We thank Denise Daley, Estee Madaschi and Rebecca Wake for their assistance in the identification and transfer of isolates, and Rebecca Martin for the manuscript review.

Financial support

Royal Perth Medical Research Foundation.

Potential conflicts of interest

All authors: no conflicts.


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Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • M. C. Wehrhahn
    • 1
    • 6
  • J. O. Robinson
    • 1
    • 2
  • J. C. Pearson
    • 2
  • F. G. O’Brien
    • 3
  • H. L. Tan
    • 2
  • G. W. Coombs
    • 1
    • 2
  • E. M. Pascoe
    • 4
  • R. Lee
    • 1
  • P. Salvaris
    • 5
  • R. Salvaris
    • 5
  • D. New
    • 5
  • R. J. Murray
    • 1
    • 5
  1. 1.Department of Microbiology and Infectious DiseasesRoyal Perth Hospital and PathWest Laboratory MedicinePerthAustralia
  2. 2.Gram-Positive Bacteria Typing and Research UnitCurtin University of TechnologyPerthAustralia
  3. 3.School of Biomedical SciencesCurtin University of TechnologyPerthAustralia
  4. 4.Clinical Research DepartmentPrincess Margaret HospitalPerthAustralia
  5. 5.Faculty of Medicine and DentistryUniversity of Western AustraliaPerthAustralia
  6. 6.Department of Microbiology and Infectious DiseasesLiverpool HospitalLiverpoolAustralia

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