Incidence, Risk Factors, Microbiology and Outcomes of Bloodstream Infection during Conditioning before Allogeneic Hematopoietic Stem Cell Transplantation

Objectives:Bloodstream infection (BSI) represents a substantial and recurrent complication that often arises during allogeneic hematopoietic stem cell transplantation (allo-HSCT). Despite its considerable occurrence, there has been a conspicuous absence of focused research delving into BSI specifically during the conditioning phase before HSCT.

Method: A single-center cohort study, comprising 2395 consecutive patients who underwent allo-HSCT from 2013 to 2023 was conducted. We examined the characteristics of BSI during the conditioning phase, risk factors and its prognosis on patients.

Results: The cumulative incidence of BSI during conditioning was 7.7%, with a median onset on day 8 post-agitation of the conditioning regimen. The most frequently isolated pathogens included Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and coagulase-negative staphylococci. A multivariate analysis identified several variables associated with BSI during conditioning, including neutropenia lasting ≥ 7 days before conditioning, a hematopoietic cell transplantation-comorbidity index ≥ 1, and in vivo T-cell depletion using antithymocyte globulin (ATG). Furthermore, the analysis indicated that BSI caused by carbapenem-resistant Enterobacteriaceae significantly increased the risk of all-cause mortality within 90 days following BSI (odd ratio = 7.492; 95% confidence interval: 1.389, 40.429; P = .019).

Conclusions: Reducing the incidence of BSI during conditioning phase can significantly improve early transplantation outcomes in haematological patients. In patients with prolonged neutropenia, comorbidities, or the inclusion of ATG in the conditioning regimen, particularly among those with multiple risk factors, the likelihood of developing BSI is significantly elevated. Therefore, it is imperative to promptly initiate blood cultures and administer timely and appropriate empiric antibiotic therapy.

No relevant conflicts of interest to declare.