Risk factors for mortality in patients with nosocomial Stenotrophomonas maltophilia pneumonia

Abstract

Objective: The aim of this study was to determine potential risk factors for mortality in patients with nosocomial Stenotrophomonas maltophilia pneumonia.

Design: A retrospective, single-center, observational study.

Setting: A 2400-bed tertiary teaching hospital in southern Taiwan.

Patients and methods: This retrospective study evaluated patients (age, at least 18 years) with nosocomial pneumonia (S. maltophilia isolated from respiratory culture) who were seen at Kaohsiung Chang Gung Memorial Hospital over a 3-year period. A total of 406 patients (64% male, mean age +/- standard deviation, 69.6 +/- 14.93 years; mean duration of hospital +/- standard deviation, 57.5 +/- 39.47 days) were included.

Results: Most index isolates (53.9%) were from the first sample cultured. Polymicrobial isolates were cultured from samples from 177 (43.6%) of the 406 study patients. The most common copathogen was Pseudomonas aeruginosa (53.11% of isolates). The all-cause hospital mortality rate was 42.6% (173 deaths among 406 patients). Survivors had a shorter time from admission to a positive index culture result than did nonsurvivors (26.1 vs 31.7 days; P = .04). Mortality was significantly higher among patients with malignancy (adjusted odds ratio [AOR], 2.48; 95% confidence interval [CI], 1.52-4.07; P < .001), renal disease (AOR, 2.6; 95% CI, 1.51-4.47; P = .001), intensive care unit stay (AOR, 1.72; 95% CI, 1.1-2.7; P = .018), and inadequate initial empirical antibiotic therapy (AOR, 2.17; 95% CI, 1.4-3.38; P = .001).

Conclusions: S. maltophilia pneumonia is associated with a high mortality rate and is commonly associated with concomitant polymicrobial colonization or infection. Underlying comorbidities and inadequate initial empirical antibiotic therapy substantially account for increased mortality rates.