Impact of methicillin resistance on outcome of Staphylococcus aureus ventilator-associated pneumonia

The impact of methicillin resistance on morbidity and mortality of patients suffering from severe Staphylococcus aureus infections remains highly controversial. We analyzed a retrospective cohort of 97 patients with methicillin-susceptible and 74 patients with methicillin-resistant Staphylococcus aureus ventilator-associated pneumonia (VAP). Initial empiric antibiotic therapy was appropriate for every patient. Patients with methicillin-resistant Staphylococcus aureus VAP were older, had higher disease-severity scores, and had been on mechanical ventilation longer at onset of VAP. Factors associated with 28-day mortality retained by multivariate logistic regression analysis were: age (odds ratio [OR] = 1.05, 95% confidence interval [CI], 1.02-1.08, p = 0.001) and Day 1 organ dysfunctions or infection (ODIN) score (OR = 1.90, 95% CI, 1.31-2.78, p = 0.001), but not methicillin resistance (OR = 1.72, 95% CI, 0.73-4.05, p = 0.22). The percentages of infection relapse or superinfection did not differ significantly between the two patient groups. in conclusion, after controlling for clinical and physiologic heterogeneity between groups, methicillin resistance did not significantly affect 28-day mortality of patients with Staphylococcus aureus VAP receiving appropriate antibiotics.