title: Prevalence of methicillin-resistant staphylococcus aureus as an etiology of community-acquired pneumonia.
abstract: BACKGROUND
  Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of skin infections. Recent case series describe severe community-acquired pneumonia (CAP) caused by MRSA, but the prevalence and risk factors are unknown.
  
  
  METHODS
  We prospectively enrolled adults hospitalized with CAP from 12 university-affiliated emergency departments during the winter-spring of 2006 and 2007. Clinical information and culture results were collected, and factors associated with MRSA were assessed.
  
  
  RESULTS
  Of 627 patients, 595 (95%) had respiratory (50%) and/or blood cultures (92%) performed. A pathogen was identified in 102 (17%); MRSA was identified in 14 (2.4%; range by site, 0%-5%) patients and in 5% of patients admitted to the intensive care unit. Two (14%) MRSA pneumonia patients died. All 9 MRSA isolates tested were pulsed-field type USA300. Features significantly associated with isolation of MRSA (as compared with any other or no pathogen) included patient history of MRSA; nursing home admission in the previous year; close contact in the previous month with someone with a skin infection; multiple infiltrates or cavities on chest radiograph; and comatose state, intubation, receipt of pressors, or death in the emergency department.
  
  
  CONCLUSIONS
  Methicillin-resistant Staphylococcus aureus remains an uncommon cause of CAP. Detection of MRSA was associated with more severe clinical presentation.
authors.affiliation: Department of Emergency Medicine, David Geffen School of Medicine at the University of California at Los Angeles (UCLA), Olive View-UCLA Medical Center, Sylmar, CA, 91342, USA. gmoran@ucla.edu
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Moran
authors.forename: Anusha
authors.initials: A
authors.lastname: Krishnadasan
authors.forename: Rachel J
authors.initials: RJ
authors.lastname: Gorwitz
authors.forename: Greg E
authors.initials: GE
authors.lastname: Fosheim
authors.forename: Valerie
authors.initials: V
authors.lastname: Albrecht
authors.forename: Brandi
authors.initials: B
authors.lastname: Limbago
authors.forename: David A
authors.initials: DA
authors.lastname: Talan
mesh_terms: D017714:Community-Acquired Infections / Q000453:epidemiology* / Q000382:microbiology*; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification*; D011023:Pneumonia, Staphylococcal / Q000453:epidemiology* / Q000382:microbiology*