Incidence, Risk Factors, Microbiology and Outcomes of Pre-engraftment Bloodstream Infection After Haploidentical Hematopoietic Stem Cell Transplantation and Comparison With HLA-identical Sibling Transplantation.

Background: Bloodstream infection (BSI) is a common and serious complication after hematopoietic stem cell transplantation (HSCT). An investigation of the characteristics of pre-engraftment BSI after haploidentical HSCT compared with human leukocyte antigen (HLA)-identical sibling HSCT has not been conducted.

Methods: A single-center cohort representing 1847 consecutive patients undergoing haploidentical or HLA-identical sibling HSCT from 2013 to 2016 was selected. We investigated the characteristics of pre-engraftment BSI after haploidentical HSCT and its impact on patient outcome, and we compared it with HLA-identical sibling HSCT.

Results: After haploidentical HSCT, the cumulative incidence of pre-engraftment BSI was higher (30-day: 9.2% [7.6, 10.8] vs 1.7% [0.5, 2.9], P < .0001) and median onset of BSI was earlier (day +3 vs day +9, P = .001) than HLA-identical sibling HSCT. Escherichia coli, Klebsiella pneumoniae, and coagulase-negative staphylococci were the most common isolates after haploidentical HSCT. However, Enterococcus faecium was the most common isolate after HLA-identical sibling HSCT. A multivariate analysis suggested that variables associated with BSI after haploidentical HSCT included a diagnosis of myelodysplastic syndrome (MDS), an interval from diagnosis to HSCT ≥190 days, carbapenem therapy, and grade 3-4 intestinal mucositis. The same variables, except MDS, were also associated with BSI after HLA-identical sibling HSCT. The multivariate analysis also suggested that BSI was a risk factor for increased all-cause mortality at 3 months after haploidentical HSCT (hazard ratio = 2.281; 95% confidence interval: 1.334, 3.900; P = .003).

Conclusions: Pre-engraftment BSI was more common after haploidentical HSCT than HLA-identical sibling HSCT. It was an independent factor associated with increased all-cause mortality at 3 months after haploidentical HSCT.