A prospective study of characteristics and outcomes of bacteremia in patients with solid organ or hematologic malignancies.

OBJECTIVE: To study the epidemiology and outcomes of bacteremia in patients with hematologic or solid organ malignancies cared for at the University Hospital of Heraklion, Greece.
METHODS: This prospective study was conducted during a 4-year period (2007-2011). Patients with bacterial and fungal blood stream infections were followed until discharge. Mortality was the primary outcome, while duration of hospitalization, relapses, time to relapse, and defervescence were the secondary outcomes.
RESULTS: Ninety-nine patients with neoplasia (104 episodes) were included. Bacteremia developed mainly in patients with hematologic malignancies (56%). Secondary bacteremias due to respiratory and urinary tract infections were most commonly identified. Gram-negative bacteria were the predominantly isolated pathogens (65%); Pseudomonas spp. was the most common cause (19%), followed closely by E. coli (18%) and Klebsiella pneumoniae (17%). In-hospital mortality was 26.2%. No differences in mortality were seen among patients in different subgroups according to isolated bacteria (according to Gram's stain, species, or number of isolated bacteria in positive cultures), hematologic or solid organ malignancy, neutropenia, and primary or secondary bacteremia. However, patients with bacteremia due to extensively drug resistant bacteria had higher mortality than patients with bacteremia due to multidrug resistant or susceptible pathogens. Patients required a prolonged period of hospitalization (21.8 ± 14.9 days), which was complicated with relapses or reinfections in another body site in 27 % of them.
CONCLUSION: Gram-negative bacteria were the predominantly isolated pathogens from patients with cancer in our population. The overall mortality remains high.