title: Patterns of early and late ventilator-associated pneumonia due to methicillin-resistant Staphylococcus aureus in a trauma population.
abstract: BACKGROUND
  Community-acquired methicillin-resistant Staphylococcal aureus (CA-MRSA) infection is approaching endemic proportions nationally, and it is a potential cause for early ventilator-associated pneumonia (VAP) in the acutely injured patient. We sought to determine the prevalence of early (≤4 days) and late (>4 days) MRSA pneumonia in ventilated multisystem trauma patients and to correlate findings with admission nasal swabs.
  
  
  METHODS
  We performed a review of our prospective trauma and infectious disease data bases for all patients admitted to our surgical intensive care unit with early (≤4 days) and late (>4 days) VAP during a 4-year period. The diagnosis of pneumonia was established by clinical pulmonary infection score >6, bronchoalveolar lavage, and quantitative cultures showing >10 organisms. Nasal swabs for early identification of MRSA carriers were performed routinely at admission.
  
  
  RESULTS
  One hundred seventy-six patients were identified with S. aureus VAP. Patients with MRSA were compared with those with methicillin-susceptible S. aureus (MSSA). There were 47 (27%) early MSSA VAP and only 4 (2.2%) with early MRSA VAP. One hundred twenty-five patients were diagnosed with late VAP. Forty patients (23%) had MRSA VAP and 85 patients (64%) had MSSA VAP. None of the four patients with an early MRSA VAP had positive nasal swabs at admission.
  
  
  CONCLUSIONS
  Despite an increase of MRSA nationally, we found a low incidence of early and late MRSA VAP in trauma patients, which was not identified by nasal swab screening. On the basis of our results, we question the efficacy of empiric vancomycin therapy in early (≤4 days) S. aureus VAP. Furthermore, nasal swabs were not helpful in identifying patients at risk for MRSA VAP.
authors.affiliation: Department of Surgery, Division of Acute Care Surgery, Penn State Hershey Medical Center and College of Medicine, Hershey, PA 17033, USA. jkashuk@hmc.psu.edu
authors.forename: Jeffry L
authors.initials: JL
authors.lastname: Kashuk
authors.forename: Ernest E
authors.initials: EE
authors.lastname: Moore
authors.forename: Connie S
authors.initials: CS
authors.lastname: Price
authors.forename: Christopher
authors.initials: C
authors.lastname: Zaw-Mon
authors.forename: Theresa
authors.initials: T
authors.lastname: Nino
authors.forename: James
authors.initials: J
authors.lastname: Haenel
authors.forename: Walter L
authors.initials: WL
authors.lastname: Biffl
authors.forename: C Cothren
authors.initials: CC
authors.lastname: Burlew
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Johnson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003120:Colorado / Q000453:epidemiology; D006801:Humans; D007362:Intensive Care Units / Q000706:statistics & numerical data; D016106:Methicillin Resistance; D055624:Methicillin-Resistant Staphylococcus aureus; D008875:Middle Aged; D011023:Pneumonia, Staphylococcal / Q000453:epidemiology* / Q000382:microbiology; D053717:Pneumonia, Ventilator-Associated / Q000453:epidemiology* / Q000382:microbiology; D015995:Prevalence; D012189:Retrospective Studies; D013997:Time Factors; D014947:Wounds and Injuries / Q000150:complications / Q000628:therapy; D055815:Young Adult