Increased mortality associated with bloodstream infections caused by Pseudomonas aeruginosa as compared to other bacteria: Results of a 13-year prospective cohort study.
Antimicrob Agents Chemother. 2017 Apr 03;:
Authors: Thaden JT, Park LP, Maskarinec SA, Ruffin F, Fowler VG, van Duin D
The impact of bacterial species on outcome in bloodstream infections (BSI) is incompletely understood. We evaluated the impact of bacterial species on BSI mortality, with adjustment for patient, bacterial, and treatment factors. From 2002-2015, all adult inpatients with monomicrobial BSI caused by Staphylococcus aureus or Gram-negative bacteria at Duke University Medical Center were prospectively enrolled. Kaplan-Meier curves and multivariable Cox regression with propensity score models were used to examine species-specific bacterial BSI mortality. Of the 2659 enrolled patients, 999 (38%) were infected with S. aureus and 1660 (62%) were infected with Gram-negative bacteria. Among patients with Gram-negative BSI, Enterobacteriaceae (81% [1343/1660]) were most commonly isolated, followed by non-lactose fermenting Gram-negative bacteria (16% [262/1660]). Of the 999 S. aureus BSI isolates, 507 (51%) were methicillin-resistant (MRSA). Of the 1660 Gram-negative BSI isolates, 500 (30%) were multidrug resistant (MDR). Unadjusted time-to-mortality among patients with Gram-negative BSI was shorter than that of patients with S. aureus BSI (p=0.003), due to increased mortality in patients with non-lactose fermenting Gram-negative BSI generally (p<0.0001) and P. aeruginosa BSI (n=158) in particular (p<0.0001). After adjustment for patient demographics, medical comorbidities, bacterial antibiotic resistance, timing of appropriate antibiotic therapy, and source control in patients with line-associated BSI, P. aeruginosa BSI remained significantly associated with increased mortality (Hazard ratio [HR] 1.435; 95% Confidence interval [CI] 1.043-1.933; p=0.02). P. aeruginosa BSI was associated with increased mortality relative to S. aureus or other Gram-negative BSI. This effect persisted after adjustment for patient, bacterial, and treatment factors.
PMID: 28373189 [PubMed - as supplied by publisher]