The impact of antimicrobial resistance and aging in VAP outcomes: experience from a large tertiary care center.

Abstract

Ventilator associated pneumonia (VAP) is a serious infection among patients in the intensive care unit (ICU). We reviewed the medical charts of all patients admitted to the adult intensive care units of the Massachusetts General Hospital that went on to develop VAP during a five year period. 200 patients were included in the study of which 50 (25%) were infected with a multidrug resistant pathogen. Increased age, dialysis and late onset (≥ 5 days from admission) VAP were associated with increased incidence of resistance. Multidrug resistant bacteria (MDRB) isolation was associated with a significant increase in median length of ICU stay (19 vs. 16 days, p=0.02) and prolonged duration of mechanical ventilation (18 vs. 14 days, p=0.03), but did not impact overall mortality (HR 1.12, 95% CI 0.51-2.46, p=0.77). However, age (HR 1.04 95% CI 1.01-1.07, p=0.003) was an independent risk factor for mortality and age ≥ 65 years was associated with increased incidence of methicillin-resistant Staphylococcus aureus (MRSA) infections (OR 2.83, 95% CI 1.27-6.32, p=0.01). MDRB-related VAP is associated with prolonged ICU stay and mechanical ventilation. Interestingly, age ≥ 65 years is associated with MRSA VAP.