Nosocomial bacteremia due to Pseudomonas spp confers significant morbidity and mortality. Identifying those at increased risk for bacteremia with a multi-drug resistant (MDR) isolate has important treatment implications. The objective of this study was to describe the incidence, mortality, patient and microbiological characteristics of Pseudomonas spp blood stream infections at a large tertiary care hospital and to identify risk factors associated with mortality and with isolation of MDR strains.
Cases of Pseudomonas spp bacteremia that occurred at a tertiary care hospital in Edmonton, Alberta between 2007 and 2014 were prospectively identified through the hospital infection prevention and control surveillance program. Charts were then retrospectively reviewed to collect further epidemiologic information.
A total of 102 incident cases of Pseudomonas bacteremia were identified (overall rate of 0.53 per 10 000 patient days). Sixty-six cases (64.7%) occurred in male patients. The most common sources of infection were the respiratory tract (22, 21.6%), urinary tract (20, 19.6%), gastrointestinal tract (19, 18.6%), and skin (15, 14.7%). Twenty-two cases (21.6%) had Pseudomonas aeruginosa isolates classified as MDR. All-cause 30-day mortality was 32.4%. Factors that predicted mortality were isolation of MDR Pseudomonas (OR 2.64, p < 0.05) a pulmonary source of infection (OR 4.33, p < 0.01), and inappropriate empiric antibiotic therapy (OR 10.98, p < 0.01). Inappropriate empiric therapy occurred more often when MDR strains were isolated (OR 5.4, p < 0.01). Factors that predicted isolation of a MDR strain were length of stay > 28 days prior to bacteremia (OR 4.45, p < 0.01), any prior intensive care unit (ICU) stay (OR 4.37, p < 0.01), hemodialysis (OR 5.23, p < 0.01), and patient age < 50 years (OR 3.16, p < 0.05).
Our study suggests that patients bacteremic with a MDR Psuedomonas spp have a higher mortality-risk, which is likely associated with inappropriate empiric antibiotic treatment. Factors that may be helpful in identifying patients at risk of having a MDR Pseudomonas bacteremia are prolonged hospitalization, prior ICU stay, hemodialysis, and younger age.
S. Smith, None