Bacteremia in patients with hematological malignancies. Analysis of risk factors, etiological agents and prognostic indicators

Abstract

Background and objective: Patients with hematological malignancies are at increased risk for developing bacteremia. No previous study has investigated the risk and prognostic indicators of bacteremia in such patients using a statistical approach.

Methods: A case-control study was performed in 106 patients with hematological malignancies (group A). Two hundred and twelve patients were included as controls and divided into two groups: 106 patients with hematological malignancy without bacteremia (group B) and 106 HIV-infected patients with bacteremia (group C).

Results: At univariate analysis, bacteremia risk factors in group A were: neutropenia for more than six days (p = 0.03 vs. group B), central venous catheter usage (p = 0.04) and absence of antibiotic prophylaxis (p = 0.03). At multivariate analysis, the use of CVC and neutropenia were independent bacteremia risk factors. The most frequent etiological agents were: Staphylococcus epidermidis and Pseudomonas aeruginosa. Comparing groups A and C, the distribution of Staphylococcus spp. was different, with S. epidermidis being prevalent in hematological patients only. As regards gram-negative organisms, it is of note that no episode of NT-Salmonella bacteremia was observed in group A, unlike group C, where they represent the second leading etiological agents. In group A, 14% of the patients died. Persistent neutropenia (p = 0.01) and the presence of relapsed neoplasm (p = 0.04) were prognostic indicators of bacteremia.

Interpretation and conclusions: Our findings suggest that bacteremia in patients with hematological malignancies strictly correlates with the intensity and length of neutropenia and CVC usage. Although we observed a low mortality rate, we stress that this clinical condition requires special attention from the physician, who must recognize and treat it promptly.