Pseudomonas aeruginosa (PA) is commonly implicated in ventilator-associated pneumonia (VAP). Consensus guidelines for VAP recommend a 7-day course of appropriate antibiotics. However, recent studies have shown higher recurrence rates of PA pneumonia with shorter courses of antibiotics. This study was designed to compare PA pneumonia recurrence rates in patients who received appropriate antibiotics for ≤7 days vs >7 days.

A retrospective, single-center, observational cohort study of adults diagnosed with PA-VAP between January 2017 and May 2022 was conducted. Patients were divided into a >7-day cohort or a ≤7-day cohort based on duration of appropriate antibiotics. The primary outcome was the recurrence rate of PA pneumonia.

A total of 106 patients were included, 59 in the >7-day cohort and 47 in the ≤7-day cohort. The median (interquartile range) duration of appropriate antipseudomonal therapy was 12 days (8–18 days) in the >7-day cohort and 7 days (6–7 days) in the ≤7-day cohort. Pseudomonas aeruginosa recurrence was observed in 15 (25.4%) patients in the >7-day cohort and 20 (42.6%) patients in the ≤7-day cohort (P = 0.059). Over 33% of patients in the >7-day cohort had persistently positive PA cultures after at least 7 days of appropriate antibiotic therapy.

Extending duration of antipseudomonal antibiotics beyond 7 days did not significantly reduce the recurrence of PA pneumonia. However, the lower rate of recurrence in the >7-day group and high rate of persistent positive cultures may be clinically significant, suggesting a role for extended treatment. Further prospective studies are needed to determine the optimal duration of therapy for PA-VAP.