title: Is methicillin resistance associated with a worse prognosis in Staphylococcus aureus ventilator-associated pneumonia?
abstract: BACKGROUND
  Excess mortality associated with methicillin resistance in patients with Staphylococcus aureus ventilator-associated pneumonia (SA-VAP), taking into account such confounders as treatment adequacy and time in the intensive care unit (ICU), have not been adequately estimated.
  
  
  METHODS
  One hundred thirty-four episodes of SA-VAP entered in the Outcomerea database were studied. Patients from whom methicillin-resistant S. aureus (MRSA) was recovered were compared with those from whom methicillin-susceptible S. aureus (MSSA) was recovered, stratified for duration of stay in the ICU at the time of VAP diagnosis and adjusted for confounders (severity at admission, characteristics at VAP diagnosis, and treatment adequacy).
  
  
  RESULTS
  Treatment was adequate within 24 h after VAP diagnosis for 86% of the 65 MSSA-infected patients and 77% of the 69 MRSA-infected patients (P = .2). Polymicrobial VAP was more commonly associated with MSSA than with MRSA (49.2% vs. 25.7%; P = .01). MRSA infection was associated with a lower prevalence of coma at hospital admission and a higher rate of use of central venous lines and fluoroquinolones during the first 48 h of the ICU stay. The rates of shock, recurrence, and superinfection were similar in both groups. The crude hospital mortality rate was higher for MRSA-infected patients than for MSSA-infected patients (59.4% vs. 40%; P = .024). This difference disappeared after controlling for time in the ICU before VAP and parameters imbalanced at ICU admission (odds ratio [OR], 1.23; 95% confidence interval [CI], 0.49-3.12; P = .7) and remained unchanged after further adjustments for initial treatment adequacy and polymicrobial VAP (OR, 0.98; 95% CI, 0.36-2.66).
  
  
  CONCLUSIONS
  Differences in patient characteristics, initial ICU treatment, and time in the ICU confounded estimates of excess death due to MRSA VAP. After careful adjustment, methicillin resistance did not affect ICU or hospital mortality rates.
authors.affiliation: Department of Microbiology, Necker Teaching Hospital, Paris, France.
authors.forename: Jean-Ralph
authors.initials: JR
authors.lastname: Zahar
authors.forename: Christophe
authors.initials: C
authors.lastname: Clec'h
authors.forename: Muriel
authors.initials: M
authors.lastname: Tafflet
authors.forename: Maite
authors.initials: M
authors.lastname: Garrouste-Orgeas
authors.forename: Samir
authors.initials: S
authors.lastname: Jamali
authors.forename: Bruno
authors.initials: B
authors.lastname: Mourvillier
authors.forename: Arnaud
authors.initials: A
authors.lastname: De Lassence
authors.forename: Adrien
authors.initials: A
authors.lastname: Descorps-Declere
authors.forename: Christophe
authors.initials: C
authors.lastname: Adrie
authors.forename: Marie-Alliette
authors.initials: MA
authors.lastname: Costa de Beauregard
authors.forename: Elie
authors.initials: E
authors.lastname: Azoulay
authors.forename: Carole
authors.initials: C
authors.lastname: Schwebel
authors.forename: Jean-Francois
authors.initials: JF
authors.lastname: Timsit
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D016106:Methicillin Resistance; D008875:Middle Aged; D011023:Pneumonia, Staphylococcal / Q000188:drug therapy* / Q000209:etiology / Q000401:mortality*; D011379:Prognosis; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000009:adverse effects*