Clinical Characteristics, Microbiology, and Risk Factors for Mortality of Pre-Engraftment and Post-Engraftment Bloodstream Infection in Hematopoietic Stem Cell Transplantation Recipients

Reduced intensity versus myeloablative conditioning for MDS: long-term results of an EBMT phase III study (RICMAC)

Short-term outcome of myeloablative (MAC) and reduced intensity (RIC) conditioning in the prospective randomized international EBMT RICMAC study in patients with myelodyplastic syndrome (MDS) was comparable but longer follow up is lacking. Patients with MDS aged 18-65 years were randomized to receive MAC (N = 64) with busulfan/cyclophosphamide or RIC (n = 65) with busulfan/fludarabine followed by stem cell transplantation -(HCT) from HLA matched or mismatched donor. After a median follow-up of 6.2 (0.4-12.5) years, 10-year OS and RFS were 54.0% and 43.9% for RIC and 44.4% and 44.2% for MAC (p = 0.15 and p = 0.78), respectively. Since the first report, 6 patients died on NRM, 4 after RIC, and 2 after MAC. Similarly, 8 patients relapsed (4 in each arm), increasing the number of relapsed patients to 28. The second HCT was performed in 18 pts, 8 in the MAC, and 10 in the RIC arm. In a multivariate analysis, ECOG status and chemotherapy prior to HCT were independent risk factors for OS and RFS, ECOG and low cytogenetic risk for NRM and chemotherapy prior to HCT for RI. Patients with low cytogenetic risk had better OS [p = 0.002], RFS [p = 0.02], and NRM (p = 0.015) after RIC as compared to MAC.

Effectiveness of Pre-Transplant Screening for High-Priority Multidrug-Resistant Pathogens on Pre-Engraftment Infections After Hematopoietic Stem Cell Transplantation

Objective

Owing to the rising incidence of multidrug-resistant organisms (MDRO) and the high mortality rates associated with such bacterial infections post-hematopoietic stem cell transplantation (HSCT), we investigated the MDRO colonization rate prior to transplantation using an active surveillance approach and determined its impact on subsequent infection during the pre-engraftment period.

Methods

A single-center observational study was conducted, and surveillance cultures from multiple body sites, including the rectum, nasal cavity, and groin, were performed at admission to determine MDRO colonization. Serological tests were used to detect certain viruses and toxoplasmosis before HSCT.

Results

In the pre-transplant setting, 59 MDRO were recovered from the 40 HSCT recipients. Of the 59 isolates recovered from one or more body sites, 29 were positive for methicillin-resistant Staphylococcus aureus (MRSA), 7 for carbapenem-resistant Enterobacterales (CRE), and 23 were positive for extended-spectrum β-lactamase (ESBLs). Serological assessment before HSCT revealed active or reactivation of latent infection with cytomegalovirus (7.5%), Epstein-Barr virus (EBV; 5%), and Toxoplasma gondii (2.5%) among HSCT patients. In terms of factors associated with pre-engraftment infections, the type of transplant (p=0.04) was statistically significant, whereas other factors, such as age, sex, and underlying conditions, were not. In post-transplant settings, bloodstream infections (BSIs) were documented in 2 allogeneic HSCT patients (5%), and the isolated microorganisms were ESBL-producing E. coli and non-MDR Acinetobacter baumannii.

Conclusion

Active screening cultures are a helpful tool for identifying patients colonized by MDRO or relevant viruses before HSCT, and for predicting those at risk of developing subsequent pre-engraftment infections. Additionally, active screening may aid in predicting those who are likely to develop subsequent pre-engraftment infections Our findings highlight the importance of pre-transplant screening for high-priority multidrug-resistant pathogens and the application of infection control interventions after HSCT.

Epidemiology of bloodstream infections and the impact of antimicrobial resistance in pediatric hematopoietic cell transplant

Bloodstream infections (BSI) pose a substantial threat to the well-being and survival of patients undergoing hematopoietic stem cell transplantation (HSCT). Risk factors for these infections vary across the different post-HSCT phases. In the pre-engraftment period, patients are particularly susceptible to infection due to prolonged neutropenia, mucosal damage, and extensive use of central venous line (CVL). In the post-engraftment phase, the emergence of graft versus host diseases further compounds the risk. The epidemiology of these infections has undergone notable changes over the years due to multifactorial reasons, including the evolution of protocols that intensify immunosuppression. In this context, the emergence of multi-drug resistance (MDR) microorganisms can be a challenge due to the elevated risk of mortality in these vulnerable patients. Unfortunately, there is a lack of comprehensive data on this topic, particularly in pediatrics. This article aims to provide a summary of the epidemiology of BSI in the different post-transplant phases and the impact of MDR pathogens. Having knowledge about the local epidemiology of BSI can be instrumental in tailoring targeted therapies, leading to improved survival rates in HSCT recipients.

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.