The Gut Microbiota in Elderly Patients with Acute Hepatitis E Infection.

Background and aims: Gut dysbiosis has been reported in severe liver diseases. However, information on the impact of hepatitis E virus infection on the gut microbiota, and the association between enteric microbiota disturbances and acute hepatitis E (AHE), is limited, particularly in elderly patients with AHE (AHE-elderly). Our objective was to characterize the AHE-specific microbiome in elderly patients and evaluate its association with clinical outcomes.

Methods: Fecal samples and clinical data were collected from 58 AHE-elderly patients (46 self-healing cases, 12 non-self-healing cases) and 30 elderly patients with healthy controls (hereinafter referred to as HCs-elderly). Gut microbiota composition was analyzed using 16S rRNA gene sequencing. Bioinformatic analyses, including alpha diversity and STAMP, were performed. The predictive potential of Bacteroides fragilis was assessed using statistical analysis and receiver operating characteristic curves.

Results: Alpha diversity indices showed no significant differences in microbial diversity between the AHE-elderly and HCs-elderly groups, nor between self-healing and non-self-healing groups among AHE-elderly patients. Nevertheless, a trend toward altered species richness was observed. In the AHE-elderly group, the relative abundance of Firmicutes, Lactobacillales, and Bacilli increased significantly. Meanwhile, compared with the self-healing group, Bacteroidetes were more abundant in the non-self-healing group. At the species level, Bacteroides fragilis was the most abundant in the non-self-healing group, significantly contributing to the divergence in gut microbiota between the two groups.

Conclusions: The relative abundance of Bacteroidetes significantly distinguished AHE-elderly patients from healthy controls and could more accurately predict recovery outcomes in elderly AHE patients. These findings suggest new strategies for preventing and managing AHE recurrence in the elderly patients.