Multidrug-resistant Pseudomonas aeruginosa lower respiratory tract infections in the intensive care unit: Prevalence and risk factors

•Multidrug-resistant (MDR) P. aeruginosa is prevalent in critically ill pneumonia patients.•MDR pneumonia risk factors are limited in a United States intensive care unit (ICU) cohort.•Prior carbapenem, fluoroquinolone, and piperacillin-tazobactam use was associated with MDR.•ICU admission from a nursing home was also associated with MDR P. aeruginosa pneumonia.•Given poor outcomes with treatment delays, ICU patients should be screened for these risk factors.

Intensive care unit (ICU) admission is a risk for multidrug-resistant (MDR) Pseudomonas aeruginosa, but factors specific to critically ill pneumonia patients are not fully characterized. Objective was to determine risk factors associated with MDR P. aeruginosa pneumonia among ICU patients. This was a retrospective case-control study of P. aeruginosa pneumonia in the ICU; cystic fibrosis and colonizers were excluded. Risk factors included comorbid conditions and prior healthcare exposure (anti-pseudomonal antibiotics, hospitalizations, nursing home, P. aeruginosa colonization/infection, mechanical ventilation). Of 200 patients, 47 (23.5%) had MDR P. aeruginosa pneumonia. Independent predictors for MDR were ≥24 h antibiotics in the preceding 90 days (carbapenems, fluoroquinolones, and piperacillin-tazobactam) (odds ratio, 3.6 [95% CI, 1.6-8.1]) and nursing home residence (2.3 [1.1-4.9]). MDR P. aeruginosa remains prevalent among ICU patients with pneumonia. Given poor outcomes with delayed therapy, patients should be thoroughly assessed for prior anti-pseudomonal antibiotic exposure and nursing home residency.