Pseudomonas aeruginosa is the leading cause of nosocomial pneumonia in the USA. Treating infections caused by this organism is challenging given the organism’s inherent resistance potential. It is unclear, however, if clinical outcomes are affected by the organism’s resistance profile. As such, the purpose of this study was to describe the clinical impact of antibiotic resistance in a group of patients with ventilator-associated pneumonia due to Pseudomonas aeruginosa.
All VAP cases between September 2001 and February 2005 that had Pseudomonas aeruginosa recovered from a respiratory culture were included in the analysis. Only the first episode of pneumonia was studied and VAP was defined according to criteria established by the American College of Chest Physicians.“Multi-drug resistant” was defined by resistance to at least 3 classes of anti-pseudomonal antibiotics.
Of the 54 cases identified, 21 (39%) were multi-drug resistant isolates.Mortality did not differ significantly between the 2 groups (50% resistant vs 44% sensitive; p=0.72). Patients with VAP caused by resistant strains, however, had longer ICU stays (53 days vs 31days; p=0.004) and were less likely to receive adequate, initial antibiotic therapy (29% vs 100%; p < 0.001). Additionally, they were more likely to be discharged to an LTAC facility (48% vs 15%; p=0.01). No antibiotic combination was associated with improved outcomes, but use of a fluoroquinolone was associated with a trend toward increased mortality and increased risk for inadequate, initial therapy.
VAP caused by resistant strains of pseudomonas aeruginosa is not associated with increased mortality as compared to VAP caused by sensitive strains. Resistant cases, however, are more often associated with longer lengths of stay and inadequate, initial antimicrobial therapy.
Fluoroquinolones should not be used as initial therapy for VAP when Pseudomonas aeruginosa is suspected.
Cheryl Weyers, None.