Prospective evaluation of the epidemiology, microbiology, and outcome of bloodstream infections in hematologic patients in a single cancer center

Abstract

Bloodstream infections (BSIs) have an important impact on the outcome of cancer patients. A prospective cohort study was undertaken at a referral cancer center in order to describe the clinical and microbiological characteristics of patients with hematologic malignancies and BSIs and to identify independent predictors associated with mortality. The study enrolled 110 consecutive BSI episodes during an 18-month period. Patients were monitored for 30 days after the last positive blood culture. There were 10.24 BSI episodes per 1,000 patient-days. The median age of the patients was 25 years. Most patients had acute leukemia ( n=72). The origin of the BSI was unknown in 43.6% of the episodes and was associated with known sites in 32.7%. There were 58 concomitant infectious sites (lungs, 43%, and soft tissue, 22.4%) and 195 noninfectious comorbid factors (poor performance status, 30.2%; undernourishment, 14.3%). The median neutrophil count was 215 cells/mm(3). Indwelling catheters were present in 70% of the episodes. The majority of isolates obtained within the first 48 h of the BSI episode (61%) were gram-negative rods. Overall mortality was 24.5%. Multivariate analysis using logistic regression showed relapsed leukemia, poor performance status, recent weight loss, and ventilatory failure requiring ventilatory support as independent predictors of mortality. Hematologic cancer patients with BSIs should be regarded as a distinct group of patients at high risk of death. The knowledge of variables amenable to intervention would help diminish or prevent serious medical complications.