Epidemiology and Infection

Original Papers

HAI, Bacterial infections

A comparison of clinical outcomes between healthcare-associated infections due to community-associated methicillin-resistant Staphylococcus aureus strains and healthcare-associated methicillin-resistant S. aureus strains

S. J. EELLSa1a2a3, J. A. McKINNELLa1a2a3, A. A. WANGa1, N. L. GREENa4, D. WHANGa4, P. O'HARAa5, M. L. BROWNa5 and L. G. MILLERa1a2a3 c1

a1 Division of Infectious Diseases, Harbor–UCLA Medical Center, and Los Angeles Biomedical Research Institute at Harbor–UCLA Medical Center, Torrance, CA, USA

a2 Infectious Disease Clinical Outcomes Research Unit (ID-CORE), Los Angeles Biomedical Research Institute at Harbor–UCLA Medical Center, Torrance, CA, USA

a3 David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, CA, USA

a4 Department of Internal Medicine, Harbor–UCLA Medical Center, Torrance, CA, USA

a5 Department of Computational Microbiology, GlaxoSmithKline, Collegeville, PA, USA


There are limited data examining whether outcomes of methicillin-resistant Staphylococcus aureus (MRSA) healthcare-associated infections (HAIs) are worse when caused by community-associated (CA) strains compared to HA strains. We reviewed all patients’ charts at our institution from 1999 to 2009 that had MRSA first isolated only after 72 h of hospitalization (n = 724). Of these, 384 patients had a MRSA-HAI according to CDC criteria. Treatment failure was similar in those infected with a phenotypically CA-MRSA strain compared to a phenotypically HA-MRSA strain (23% vs. 15%, P = 0·10) as was 30-day mortality (16% vs. 19%, P = 0·57). Independent risk factors associated with (P < 0·05) treatment failure were higher Charlson Comorbidity Index, higher APACHE II score, and no anti-MRSA treatment. These factors were also associated with 30-day mortality, as were female gender, older age, MRSA bloodstream infection, MRSA pneumonia, and HIV. Our findings suggest that clinical and host factors, not MRSA strain type, predict treatment failure and death in hospitalized patients with MRSA-HAIs.

(Received August 24 2012)

(Revised October 29 2012)

(Accepted October 29 2012)

(Online publication December 07 2012)

Key words

  • Community-associated;
  • genotype;
  • healthcare-associated;
  • MRSA;
  • outcomes


c1 Author for correspondence: L. G. Miller, M. D., M. P. H., Associate Professor of Medicine, David Geffen School of Medicine at UCLA, Division of Infectious Diseases, Harbor-UCLA Medical Center, 1000 W Carson St, Box 466, Torrance CA 90509, USA. (Email: Lgmiller@ucla.edu)