Girmenia C, et al. - In view of gram-negative bacteremia (GNB) as a major cause of illness and death after hematopoietic stem cell transplantation (HSCT), researchers performed an updated epidemiological investigation. They recognized pre-engraftment GNB as an independent factor associated with increased mortality rate at 4 months after auto-HSCT and allo-HSCT. Major indicators of GNB included previous infectious history and colonization monitoring.

Methods

• Among 54 transplant centers during 2014 (SIGNB-GITMO-AMCLI study), the epidemiology of pre-engraftment GNB was prospectively evaluated in 1118 allogeneic HSCTs (allo-HSCTs) and 1625 autologous HSCTs (auto-HSCTs).
• They assessed risk factors for GNB and evaluated the impact of GNB on the 4-month overall-survival after transplant using logistic regression methods.

Results

• Findings revealed the cumulative incidence of pre-engraftment GNB in allo-HSCT of 17.3% and 9% in auto-HSCT.
• The most common isolates included Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa.
• Multivariate analysis suggested that variables associated with GNB were a diagnosis of acute leukemia, a transplant from a HLA-mismatched donor and from cord blood, older age, and duration of severe neutropenia in allo-HSCT, and a diagnosis of lymphoma, older age, and no antibacterial prophylaxis in auto-HSCT.
• Researchers noticed a significant association of a pretransplant infection by a resistant pathogen with an increased risk of posttransplant infection by the same microorganism in allo-HSCT.
• In both transplant procedures, colonization by resistant gram-negative bacteria seemed markedly associated with an increased rate of infection by the same pathogen.
• They identified GNB as an independent factor associated with increased mortality at 4 months both in allo-HSCT (hazard ratio, 2.13; 95% confidence interval, 1.45–3.13; P <.001) and auto-HSCT (2.43; 1.22–4.84; P=.01).