Sarbecovirus-associated gut microbiome instability in a natural bat reservoir

Sarbecoviruses, a subgenus of Betacoronavirus, display both respiratory and gastrointestinal tropism, suggesting potential interactions with host gut microbial communities. However, ecological signatures of infection in wild bats remain poorly understood. We investigated associations between Sarbecovirus infection status, gut microbiome structure, and diet composition in Rhinolophus shameli roosting in northeastern Cambodia. Fecal samples collected across dry and wet seasons (2023-2024) were subject to full-length 16S rRNA gene sequencing and arthropod DNA metabarcoding. Sarbecovirus-positive bats exhibited stable alpha diversity but consistent shifts in gut community composition and increased interindividual variability consistent with the Anna Karenina Principle, suggesting infection-associated destabilization of community assembly rather than diversity erosion. Infection status was associated with enrichment of Shigella and Escherichia species, taxa linked to inflammatory or epithelial stress states in bats. In contrast, dietary composition showed no strong global structuring by infection status and weak coupling with bacterial community structure, suggesting that trophic ecology is unlikely to be the main driver of the infection-associated microbiome signal. Although causal directionality cannot be inferred, our results reveal measurable and consistent microbiome restructuring associated with Sarbecovirus detection in a natural reservoir host and highlight the potential of microbiome profiling for monitoring wildlife disease processes.