Bloodstream Infection In Patients With Malignant Hematologic Disease After Unrelated Cord Blood Transplantation During Early Posttransplant Period:a Retrospective Study

Purpose: Bloodstream infection(BSI)is one of the major causes of mortality in patients undergoing allogeneic hematopoietic stem cell transplantation(allo-HSCT).The incidence and characteristics of pathogenic microorganisms of BSI,and its effect on prognosis differ among varied sources of graft,transplantation programs,transplantation periods,and transplant centers.Over the past few decades,for the rapid growth of allo-HSCT,especially the development of alternative donor transplantation,the shortage of allo-HSCT donors has been changed completely.Today,almost all patients to go through allo-HSCT can find suitable donors.However,infections after transplantation are still a main cause of allo-HSCT failure,and alternative donor transplantation in particular.For patients with malignant hematologic disease who have no HLA matched genetic donors,UCB is a valuable alternative donor.Nevertheless,studies at home and abroad on severe infections(such as BSI)after UCBT are rarely found.The aim of this study was to analyze the incidence and risk factors of BSI,causative organisms,microbial resistance,and its impact on the clinical outcomes and survival of patients.Methods: This retrospective analysis included 336 patients with malignant hematologic disease that received myeloablative UCBT in The First Affiliate Hospital of University of Science and Technology of China(Anhui Provincial Hospital)during the period from January 2012 to January 2017.Patients were divided into two groups depending on whether or not experienced BSI during early post-transplantation period,and statistics of their BSI incidence,specific pathogenic species,and their resistance to various antibiotics collected.Demographic characteristics,laboratory data,and clinical outcome were compared between the two groups,and then analyzed with logistic regression analysis to find out independent risk factors of BSI.After that,BSI infections were further divided into three groups by multiple drug resistance infections,their survival data recorded,and the overall survival(OS)of the two groups compared using the Kaplan-Meier method and log-rank test.Disease-free survival(DFS)was studied with survival analysis with competitive risk.Results: In all 336 patients,92(27.4%)were recorded to have early BSI,5 with twice the occurrence of BSI,and 4 with two types of pathogenic bacteria in the same blood culture.The median day of initial BSI was 4.5 d,and that of Gram-postive bacteria BSI +6 d(ranging-3 to +36 d),significantly later than that of Gram-negative bacteria BSI being +4 d(ranging 0 to +30 d,p=0.039).Finally,101 pathogenic bacteria were isolated,of which 60 were Gram-negative bacteria(59.4%),40 were Gram-positive bacteria(39.6%),and 1 was fungi(Candida albicans).The predominant Gram-negative bacteria in descending order were as follows: Escherichia coli(39 isolates),Klebsiella pneumoniae(9 isolates),and Pseudomonas aeruginosa(6 isolates).The predominant Gram-positive bacteria were Streptococcus viridans(10 isolates),Staphylococcus epidermidis(9 isolates),Enterococcus faecium(7 isolates),and Streptococcus mitis(7 isolates).In addition,we recorded 37 isolates of MDR,all Gram-negative bacteria(5 were Klebsiella pneumonia,and 32 Escherichia coli).By multivariate analysis,myeloid malignancies,conditioning regimens including total body irradiation(TBI),and prolonged neutropenia were identified as the independent risk factors for early BSI after transplatation.The 3-year OS was 59.9%(95%CI,0.489-0.692)versus 69.2%(95%CI,0.622-0.752)in the BSI group and non-BSI group,no statistically significant difference(P=0.0574).The 3-year OS of the MDR group was significantly lower than that of the non-BSI group(51.1%(95%CI,0.341-0.658)versus 69.2%(95%CI,0.622-0.752),p=0.013).We also analyzed the 100-day OS after UCBT of these three groups,and no significant difference was found.Conclusion:(1)The incidence of early BSI after UCBT was high in patients with malignant hematologic disease;(2)In patients with malignant hematologic disease that received UCBT,myeloid disease,a conditioning regimen including TBI,and prolonged neutropenia were independent risk factors for early BSI after transplantation;(3)In patients with malignant hematologic disease that received UCBT,early BSI with MDR after UCBT had a negative impact on long-term survival.