title: Methicillin-Resistant Staphylococcus aureus Pneumonia in Critically Ill Trauma and Burn Patients: A Retrospective Cohort Study.
abstract: BACKGROUND
  The timing and risk factors for methicillin-resistant Staphylococcus aureus (MRSA) pneumonia in trauma patients are not well characterized. This information is critical for the selection of appropriate empiric antibiotics. The objective of this study was to determine the incidence of MRSA pneumonia in early-onset and late-onset pneumonia and to identify risk factors for MRSA in the trauma-burn intensive care unit (ICU).
  
  
  METHODS
  We conducted a retrospective cohort study from January 2012 to March 2015 of patients in the trauma and burn ICU with clinical and microbiologic evidence of pneumonia. Demographics, injury type and severity, co-morbidities, antimicrobial agents, and MRSA nasal colonization at ICU admission were extracted from the medical record. A multi-variable exact logistic regression was performed to assess predictors of MRSA pneumonia.
  
  
  RESULTS
  Eighty patients with 88 episodes of pneumonia were included in the cohort. Ten patients had MRSA pneumonia, an overall incidence of 11.4% of pneumonia episodes with a median onset of seven days. The proportion of MRSA pneumonia episodes was not significantly different in early-onset (<5 days) or late-onset pneumonia, and there were no statistically significant risk factors for developing MRSA pneumonia. The majority of patients with MRSA had at least one known risk factor including homelessness, substance abuse, and receipt of broad-spectrum antibiotic agents.
  
  
  CONCLUSIONS
  The 11.4% overall incidence of MRSA pneumonia in this trauma-burn cohort was similar to what has been reported in other trauma populations, although MRSA was equally likely to be identified in early- and late-onset pneumonia. Our results suggest that risk factors other than duration of hospitalization may be important considerations in the decision to initiate MRSA-active empiric therapy for pneumonia in the trauma-burn ICU.
authors.affiliation: 1 Department of Pharmacy, Rhode Island Hospital , Providence, Rhode Island.
authors.forename: Kristen L
authors.initials: KL
authors.lastname: Bunnell
authors.affiliation: 1 Department of Pharmacy, Rhode Island Hospital , Providence, Rhode Island.|2 Department of Health Services, Policy, and Practice, Brown University School of Public Health , Providence, Rhode Island.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Zullo
authors.affiliation: 1 Department of Pharmacy, Rhode Island Hospital , Providence, Rhode Island.
authors.forename: Christine
authors.initials: C
authors.lastname: Collins
authors.affiliation: 3 Department of Surgery, Rhode Island Hospital, The Warren Alpert Medical School of Brown University , Providence, Rhode Island.
authors.forename: Charles A
authors.initials: CA
authors.lastname: Adams
mesh_terms: D000328:Adult; D000368:Aged; D002056:Burns / Q000453:epidemiology / Q000382:microbiology; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology; D005260:Female; D006801:Humans; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus; D008875:Middle Aged; D011023:Pneumonia, Staphylococcal / Q000453:epidemiology / Q000382:microbiology; D012189:Retrospective Studies; D014947:Wounds and Injuries / Q000453:epidemiology / Q000382:microbiology
keywords: hospital-acquired pneumonia; trauma; ventilator-associated pneumonia