| Background and ObjectivesAllogeneic hematopoietic stem cell transplantation is the only way to cure malignant hematological diseases.However,due to the application of high-dose radiotherapy,chemotherapy and immunosuppressive agents,most transplant patients experience a long-term period of agranulocytosis,with extremely low immunity,and often accompanied by mucosal barrier damage,which is very prone to bloodstream infection.Bloodstream infection progresses rapidly and has a poor prognosis.Especially in recent years,the resistance of pathogens to antibiotics has continued to increase,which has further increased the difficulty of clinical antibacterial treatment.Multi-drug resistant bacteria,especially Carbapenem-resistant Enterobacter(CRE),are prone to colonization in the intestines.Colonized CRE can cause bloodstream infections through intestinal bacterial translocation,and the mortality rate of CRE bloodstream infection is extremely high,which seriously affects the overall survival of transplant patients.Therefore,it is important to understand the changes of pathogenic bacteria and antimicrobial spectrum in local transplantation centers,actively monitor the intestinal colonization of CRE in allo-HSCT patients,and develop timely and effective anti-infection strategies to improve the efficacy of transplantation.This study mainly explored the occurrence of bloodstream infections in patients with allo-HSCT.The study was divided into two phases.The first phase was to analyze the incidence of bloodstream infections,pathogen types,antibiotic susceptibility and risk factors in allo-HSCT patients with agranulocytosis.In the second stage,patients with allo-HSCT were actively screened by perianal swabs to assess the incidence of CRE colonization and the distribution of pathogens,and explore the relationship between CRE colonization and bloodstream infections,in order to provide a basis for clinical anti-infective treatment.Cases and MethodsIn the first stage,397 hematological patients who underwent allo-HSCT at the First Affiliated Hospital of Zhengzhou University from January 2013 to December 2017 were included.We collected the clinical data of the patients and performed retrospective analysis to count the incidence of bloodstream infection,the distribution of pathogenic bacteria and the resistance to antibiotics.The patients were divided into two groups according to whether the patients had bloodstream infections,and compared the characteristics of the two groups in terms of gender,age,primary disease,transplantation method,and anti-thymocyte globulin(ATG)application.Chi-square test and logistic regression were used for statistical analysis to explore the risk factors of bloodstream infection.In the second stage,106 patients with hematological diseases who underwent alloHSCT at the Hematopoietic Stem Cell Transplant Center of our hospital from May 2019 to December 2020 were actively screened by perianal swabs,and the perianal swabs were tested for bacterial culture.The species of pathogens of CRE,the rate of CRE colonization,the incidence of bloodstream infection and the distribution of pathogens of CRE colonization patients were statistically analyzed,and the risk factors of CRE colonization were analyzed from the aspects of gender,age,primary disease,disease remission status,ICU admission history,carbapenem antibiotic exposure history,etc.ResultsIn the first phase of the study,among 397 allo-HSCT patients,the proportion of fever during agranulocytosis was 74.1%(294/397),and the incidence of BSI was 17.7%(52/294).Among 60 strains of pathogens,71.67%of gram-negative bacteria,16.67%of gram-positive bacteria,and 11.66%of fungi,and Escherichia coli was the most common pathogen.Among the detected enterobacteria,CRE accounted for 17.9%(5/28),The detection rates of extended-spectrum β-lactamase in Escherichia coli and Klebsiella pneumoniae were 46.7%and 30%,respectively.Univariate and multivariate analysis showed that the risk factors for bloodstream infections were the use of ATG,the duration of agranulocytosis(≥21d),and the source of stem cells(peripheral blood stem cells,cord blood stem cells).In the second phase of the study,106 patients who took the initiative to undergo perianal swab screening,the CRE colonization rate was 28.3%(30/106),and 32 strains of CRE were screened,including 15 strains of carbapenem-resistant Klebsiella pneumonia and 14 strains of carbapenem-resistant Escherichia coli.Five of the 30 colonized patients developed bloodstream infections during transplantation,and all the pathogens in blood culture were carbapenem-resistant Klebsiella pneumonia.The drug resistance of the pathogens was highly consistent with that of the perianal swabs screened for pathogens.Three of the five patients with CRE bloodstream infection died,and the mortality rate was 60%.Univariate analysis found that the 3-month history of exposure to carbapenem antibiotics was related to CRE colonization.Conclusions1.The pathogens of bloodstream infections in allo-HSCT patients in our hospital were mainly Gram-negative bacteria,followed by Gram-positive bacteria.The proportion of fungi were the lowest,and carbapenems had a high resistance rate.2.The use of ATG for pretreatment,the duration of agranulocytosis(≥21),and the source of stem cells(peripheral blood stem cells,cord blood stem cells)were risk factors for bloodstream infections.3.The pathogens of allo-HSCT patients in our hospital were mainly carbapenemresistant Klebsiella pneumoniae and carbapenem-resistant Escherichia coli for screening perianal swabs,and the pathogens of bloodstream infections in patients with CRE colonization were mainly carbapenem-resistant Klebsiella pneumoniae.4.The history of exposure to carbapenem antibiotics within 3 months before transplantation was related to the occurrence of CRE colonization in allo-HSCT patients during transplantation. |
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