Impact of anti-anaerobic antibiotic activity on graft-versus-host disease in allogeneic hematopoietic stem cell transplant (HSCT) recipients at an institution that utilizes antibiotic cycling

Effect of Antibiotics With Anaerobic Coverage on Graft-Versus-Host Disease in Patients Undergoing Allogeneic Hematopoietic Stem Cell Transplantation: A Systematic Review and Meta-Analysis

BACKGROUND

Broad-spectrum antibiotics are standard for febrile neutropenia (FN) in allogeneic hematopoietic stem cell transplantation (HSCT) but may disrupt gut microbiota, increasing the risk of graft-versus-host disease (GVHD). However, current evidence on the effects of anaerobic versus limited anaerobic antibiotic coverage on GVHD-related outcomes remains inconclusive.

METHODS

We systematically searched for studies assessing overall survival, acute GVHD incidence, and GVHD-related mortality in patients with allogeneic HSCT receiving antibiotics with anaerobic versus limited anaerobic coverage. A random-effects meta-analysis calculated risk ratios (RRs) and 95% confidence intervals (CIs) after assessing bias risk.

RESULTS

Six of the 323 screened studies met the inclusion criteria, encompassing 2169 patients: five studies included adult populations, and one included a pediatric population. Meta-analysis revealed no significant difference in 1-year overall survival between the anaerobic and the limited anaerobic coverage groups (RR: 1.01; 95% CI: 0.92-1.12). Acute GVHD incidence was significantly higher in the anaerobic coverage group than in the limited anaerobic coverage group (RR: 1.33; 95% CI: 1.17-1.51). GVHD-related mortality tended to be higher in the anaerobic coverage group than in the limited coverage group (RR: 1.65; 95% CI: 0.94-2.91). Of the six studies, three had a high risk of bias. Moderate heterogeneity was observed between citations regarding GVHD-related mortality (I2 = 63%).

CONCLUSION

Antibiotics with anaerobic coverage appear to increase acute GVHD incidence in patients who received an allogeneic HSCT compared to antibiotics with limited anaerobic coverage. However, the strength of this conclusion is limited by the quality of available evidence. Further well-designed research is necessary to clarify the impact of anaerobic antibiotic coverage on GVHD-related outcomes.

Antibiotic Exposure and Risk of Allograft Rejection and Survival After Liver Transplant: An Observational Cohort Study From a Tertiary Referral Centre

INTRODUCTION

Our goal is to understand whether there is an association between Abx exposure-and the inferred downstream damage to the intestinal microbiome-and the key patient outcomes of overall survival and rejection following liver transplant.

METHODS

We conducted a retrospective cohort study of 462 liver transplant recipients treated at a multistate liver transplant (LTx) service during a 7-year period. The association between antibiotic exposure and outcome was tested across models that addressed antibiotic spectrum, duration, and timing relative to transplant. Cox proportional hazard regression was used to evaluate the relationship between antibiotics with survival and rejection.

RESULTS

The observed 1-year survival in this cohort was 95% (95% CI: 93%, 97%), and 20.8% of patients (96/462) experienced rejection at 1 year. In multivariable analyses, exposure to anaerobe-targeting antibiotics for longer than 14 days pretransplant (p = 0.055) or posttransplant (p = 0.040) was significantly associated with reduced 1-year survival. In multivariable analyses, exposure to any anaerobe-targeting Abx posttransplant was significantly associated with an increased risk of rejection (p = 0.001).

CONCLUSIONS

Exposure to anaerobic spectrum antibiotics either before or after LTx was associated with poor outcomes during the first year posttransplant and provides an impetus to further characterize the relationship between antibiotic use, microbiota disruption, and cellular immunity in liver transplantation.

Microbiome Modulation in Pediatric Leukemia: Impact on Graft-Versus-Host Disease and Treatment Outcomes: A Narrative Review

The gut microbiome significantly influences the outcomes of pediatric leukemia, particularly in patients undergoing hematopoietic stem cell transplantation (HSCT). Dysbiosis, caused by chemotherapy, antibiotics, and immune system changes, contributes to complications such as graft-versus-host disease (GVHD), gastrointestinal issues, and infections. Various microbiome-related interventions, including prebiotics, probiotics, postbiotics, and fecal microbiota transplantation (FMT), have shown potential in mitigating these complications. Specific microbial signatures have been linked to GVHD risk, and interventions like inulin, Lactobacillus, and SCFAs (short-chain fatty acids), particularly butyrate, may help modulate the immune system and improve outcomes. FMT, while showing promising results in restoring microbial balance and alleviating GVHD, still requires careful monitoring due to potential risks in immunocompromised patients. Despite positive findings, more research is needed to optimize microbiome-based therapies and ensure their safety and efficacy in pediatric leukemia care.

Analysis of Antibiotic Exposure and Development of Acute Graft-vs-Host Disease Following Allogeneic Hematopoietic Cell Transplantation

Importance

Certain antibiotic exposures have been associated with increased rates of acute graft-vs-host disease (aGVHD) after allogeneic hematopoietic cell transplantation (allo-HCT). Since antibiotic exposure can both affect and be affected by infections, analyzing time-dependent exposure in the presence of multiple potential confounders, including prior antibiotic exposures, poses specific analytical challenges, necessitating both a large sample size and unique approaches.

Objective

To identify antibiotics and antibiotic exposure timeframes associated with subsequent aGVHD.

Design, Setting, and Participants

This cohort study assessed allo-HCT at a single center from 2010 to 2021. Participants included all patients aged at least 18 years who underwent their first T-replete allo-HCT, with at least 6 months of follow-up. Data were analyzed from August 1 to December 15, 2022.

Exposures

Antibiotics between 7 days before and 30 days after transplant.

Main Outcomes and Measures

The primary outcome was grade II to IV aGVHD. The secondary outcome was grade III to IV aGVHD. Data were analyzed using 3 orthogonal methods: conventional Cox proportional hazard regression, marginal structural models, and machine learning.

Results

A total of 2023 patients (median [range] age, 55 [18-78] years; 1153 [57%] male) were eligible. Weeks 1 and 2 after HCT were the highest-risk intervals, with multiple antibiotic exposures associated with higher rates of subsequent aGVHD. In particular, exposure to carbapenems during weeks 1 and 2 after allo-HCT was consistently associated with increased risk of aGVHD (minimum hazard ratio [HR] among models, 2.75; 95% CI, 1.77-4.28), as was week 1 after allo-HCT exposure to combinations of penicillins with a β-lactamase inhibitor (minimum HR among models, 6.55; 95% CI, 2.35-18.20).

Conclusions and Relevance

In this cohort study of allo-HCT recipients, antibiotic choices and schedules in the early course of transplantation were associated with aGVHD rates. These findings should be considered in antibiotic stewardship programs.