Epidemiology and Infection

Original Papers

MRSA and HAI

A population-based study of the epidemiology and clinical features of methicillin-resistant Staphylococcus aureus infection in Pennsylvania, 2001–2010

J. A. CASEYa1, S. E. COSGROVEa2a4, W. F. STEWARTa2a5, J. POLLAKa1 and B. S. SCHWARTZa1a2a3a5 c1

a1 Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA

a2 Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA

a3 Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA

a4 Division of Infectious Disease, Johns Hopkins School of Medicine, Baltimore, MD, USA

a5 Center for Health Research, Geisinger Health System, Danville, PA, USA

SUMMARY

No U.S. general population-based study has characterized the epidemiology and risk factors, including skin and soft tissue infection (SSTI), for healthcare-associated (HA) and community-associated (CA) methicillin-resistant Staphylococcus aureus (MRSA). We estimated the incidence of HA- and CA-MRSA and SSTI over a 9-year period using electronic health record data from the Geisinger Clinic in Pennsylvania. MRSA cases were frequency-matched to SSTI cases and controls in a nested case-control analysis. Logistic regression was used to assess risk factors, while accounting for antibiotic administration. We identified 1713 incident CA- and 1506 HA-MRSA cases and 78 216 SSTI cases. On average, from 2005 to 2009, the annual incidence of CA-MRSA increased by 34%, HA-MRSA by 7%, and SSTI by 4%. Age, season, community socioeconomic deprivation, obesity, smoking, previous SSTI, and antibiotic administration were identified as independent risk factors for CA-MRSA.

(Received June 20 2012)

(Revised July 30 2012)

(Accepted July 31 2012)

(Online publication August 29 2012)

Key words

  • Epidemiology;
  • incidence;
  • methicillin-resistant S. aureus (MRSA);
  • skin infections

Correspondence

c1 Author for correspondence: Dr B. S. Schwartz, Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Room W7041, Baltimore, MD, 21205, USA. (Email: bschwart@jhsph.edu)

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