Profile and Antibiotic Pattern of Blood Stream Infections of Patients Receiving Hematopoietic Stem Cell Transplants in Southwest China

Systematic review on epidemiology of Escherichia coli in bloodstream infection of patients undergoing hematopoietic stem cell transplantation

Introduction

We aimed to conduct a systematic review of the epidemiology of Escherichia coli in bloodstream infections (BSI) of hematopoietic stem cell transplantation patients.

Methods

For a comprehensive search of studies that reported the prevalence of E. coli and antibiotic resistance in bloodstream infections from 2000 to January 1, 2024, databases such as PubMed, EMBASE, Google Scholar, Scopus, and Web of Science were searched. The main keywords used were: Escherichia coli, epidemiology, bloodstream infection, microbial resistance, antibiotic resistance, hematopoietic malignancy, hematopoietic stem cell transplantation. After applying eligibility criteria, and quality assessment of studies, data analysis was done by comprehensive meta-analysis (CMA) software.

Results

The prevalence of bacterial bloodstream infections amongst different studies varied between 8-51%. Also, bloodstream infections caused by E. coli varied between 2.5-57%. Prevalence of extended-spectrum β-lactamases (ESBLs) of Escherichia coli in bloodstream infections varied between 15-80%. As well, the mortality rate caused by Escherichia coli strains in bloodstream infection varied between 6.7-27.3%. Resistance to ciprofloxacin, cefepime, third- and fourth-generation cephalosporins, was reported to be the highest (prevalence of 100%), and the lowest was against amikacin, with a prevalence between 13-38%.

Conclusions

The high prevalence of Escherichia coli-related BSI, and subsequent mortality, especially by multidrug resistance and ESBL strains, in patients undergoing hematopoietic stem cell transplantation, requires essential measures to prevent the spread of microbial resistance.

Microbiology and Clinical Outcome of Bloodstream Infections in Patients After Hematopoietic Stem Cell Transplantation

Purpose

Patients after hematopoietic stem cell transplantation (HSCT) are often followed by bloodstream infections (BSIs). BSI is an important cause of non-relapse mortality (NRM) in HSCT patients.

Methods

We conducted a retrospective cohort study of patients (aged >14 years) who underwent HSCT at our hospital from 2017 to 2021. Population characteristics, BSI microbiology, resistance to common antibiotics, and 30-day all-cause mortality were analyzed.

Results

Of 3054 patients, 169 (5.5%) had BSIs after HSCT. Male, not in complete remission at transplantation and longer duration of neutropenia were risk factors for the development of BSI after HSCT. These BSIs were Gram-negative bacterial (n=123, 69.49%), Gram-positive bacterial (n=27, 15.25%), fungal (n=11, 6.36%), and polymicrobial (n=16, 9.25%). Among the Gram-negative bacteria, the proportions of isolates resistant to ceftazidime, cefepime, and piperacillin-tazobactam were similar (72.93%, 74.80%, and 77.42%, respectively). The overall drug resistance rates of amikacin and imipenem were 16.13% and 43.90%, respectively. Staphylococcus isolates were methicillin-resistant. In Enterococcus isolates, the penicillin resistance rate was 84.62%. Eleven isolates of Candida tropicalis were resistant to fluconazole and were sensitive to amphotericin B and flucytosine. The 30-day all-cause mortality rate of the 169 patients with BSIs was 8.88%. The 30-day all-cause mortality of patients with Gram-negative bacterial BSIs was 7.32%, 25.00% for polymicrobial BSIs, and 36.36% for fungal BSIs. The 30-day all-cause mortality of patients with fungal BSIs was significantly higher than that of patients with Gram-negative (P=0.0023) and Gram-positive bacteria (P=0.0023). Fungal BSI and non-Hodgkin's lymphoma (NHL) were associated with higher 30-day mortality.

Conclusion

Our study reveals the microbiological characteristics and 30-day all-cause mortality in patients with bloodstream infections after HSCT. Our data provides strong support for empirical antimicrobial therapy and infection prevention strategies for patients with BSIs after HSCT.

Active Screening of Intestinal Colonization of Carbapenem-Resistant Enterobacteriaceae for Subsequent Bloodstream Infection in Allogeneic Hematopoietic Stem Cell Transplantation

Purpose

To investigate the prevalence, risk factors of intestinal carbapenem-resistant Enterobacteriaceae (CRE) colonization and bloodstream infection (BSI) caused by CRE in allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients.

Methods

We analyzed the clinical data of 185 patients with hematological malignancies who underwent allo-HSCT from May 2019 to December 2021. All patients received regular CRE monitoring by rectal swab during allo-HSCT, and some CRE strains were further identified for carbapenemase phenotypes. The rates, distribution and risk factors of CRE colonization, CRE-induced BSI were analyzed.

Results

CRE was detected in 44 of 185 recipients, with colonization rate of 23.8%. A total of 46 strains of CRE were isolated, including 22 Escherichia coli, 17 Klebsiella pneumoniae, three Klebsiella oxytoca, two Enterobacter hormaechei, and two other Enterobacteriaceae. Among the 19 strains identified with carbapenemase phenotypes, eight strains of E. coli produced metal β-lactamase, five K. pneumoniae produced serine carbapenemase, two K. pneumoniae produced metal β-lactamase, two K. oxytoca produced metal β-lactamase, a Citrobacter malonic acid-free produced metal β-lactamase and a Citrobacter freundii produced metal β-lactamase. In 10 patients developed with CRE-related BSI, the types and combined drug sensitivity of strains detected by rectal swab were highly consistent with blood culture. Multivariate analysis revealed that pulmonary infection, perianal infection and carbapenem application in the 3 months pre-transplant were independent risk factors for rectal CRE colonization, while rectal colonization with carbapenem-resistant K. pneumoniae (CR-KP) was an independent risk factor for CRE-induced BSI. The mortality rate within 30 days of CRE-related BSI was 50.0%, and patients receiving multi-drug therapy within 24 hours showed slightly lower mortality than that in the single-drug treatment group.

Conclusion

Allo-HSCT patients with CRE-induced BSI have poor prognosis, and CR-KP rectal colonization is an independent risk factor for CRE-related BSI. Rectal swab screening during allo-HSCT could provide early warning for later CRE-induced BSI.