title: Empiric Methicillin Resistant Staphylococcus aureus Coverage in the Early Ventilator Associated Pneumonia Window: If and When.
abstract: BACKGROUND
  Choice of empiric antibiotic(s) for early ventilator associated pneumonia (VAP) involves weighing the risks of potential infection with multi-drug resistant (MDR) pathogens against those of over-exposure to broad-spectrum agents. Although early VAP is believed to be rarely caused by MDR pathogens, the overall incidence of all methicillin resistant Staphylococcus aureus (MRSA) infections is increasing. We questioned if MRSA VAP is becoming more common and if these infections were occurring earlier in the patient's hospital course. We hypothesized that 1) early (2-4 d from intubation) VAP caused by MRSA is relatively uncommon and 2) those patients with early VAP because of MRSA had risk factors associated with a MDR organism infection.
  
  
  METHODS
  Bronchoscopies with lavage (BALs) from patients admitted to our SICU from 2010-2013 were reviewed. MRSA VAP was defined as growth of ≥10(5) cfu/mL from BAL. Multi-drug resistant risk factors included a previous MRSA infection or positive nasal swab, antibiotic use within 90 d, hospitalization for >5 d, hemodialysis, homelessness, intravenous drug use, and men having sex with men.
  
  
  RESULTS
  In the 3-y period, there were 438 cases of VAP. Forty-seven specimens from 43 patients had quantitative microbiologic confirmation of MRSA VAP for an overall prevalence of 10.7%. Of patients with early VAP, three of 106 (2.8%) were MRSA positive. Culture results were graphed according to ventilator days ( Fig. 1 ). The median days ventilated at the time of MRSA VAP were 8 d (range 2-81). All of the early MRSA VAP patients had identifiable risk factors for MRSA infection. The negative predictive value for patients not having a risk factor was one.
  
  
  CONCLUSIONS
  These data suggest that the incidence of MRSA VAP is stable. Those patients with early MRSA VAP demonstrated traditional MDR risk factors. Patients without risk factors in the early time period could effectively be ruled out from having MRSA VAP and likely do not require empiric MRSA coverage.
authors.affiliation: Denver Health Medical Center , Denver, Colorado.
authors.forename: Daniel I
authors.initials: DI
authors.lastname: Lollar
authors.affiliation: Denver Health Medical Center , Denver, Colorado.
authors.forename: Maridi
authors.initials: M
authors.lastname: Rodil
authors.affiliation: Denver Health Medical Center , Denver, Colorado.
authors.forename: Benoit
authors.initials: B
authors.lastname: Herbert
authors.affiliation: Denver Health Medical Center , Denver, Colorado.
authors.forename: Clay Cothren
authors.initials: CC
authors.lastname: Burlew
authors.affiliation: Denver Health Medical Center , Denver, Colorado.
authors.forename: Fredric M
authors.initials: FM
authors.lastname: Pieracci
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology; D001999:Bronchoscopy; D024901:Drug Resistance, Multiple, Bacterial; D006801:Humans; D015994:Incidence; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000302:isolation & purification*; D008875:Middle Aged; D053717:Pneumonia, Ventilator-Associated / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology*; D012189:Retrospective Studies; D055502:Secondary Prevention / Q000379:methods; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology*; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents