The bee gut microbiota bridges pathogens and virulence traits in a one health perspective

The microbiota of the gastrointestinal tract of bees plays a crucial role in the services they provide to the environment, as well as to humans and animals. Moreover, microorganisms harbored in the bee gut are moved, with the bee flies, between seemingly distant habitats. This promotes microbial heterogeneity of the visited microcosms and facilitates the exchange of genetic material among microbes at both intra- and inter-kingdom level, with strong influences on the functional array of the entire microbial community. Thus, studying the functional concern of the bee gut microbiota might represent a suitable strategy for monitoring and forecasting microbial dynamics and evolutions. Here, only a paucity of studies are available in the literature, most of which deal with the definition of the bee gut microbiota composition; whereas, very few aim at the functional investigation of the sole bacterial fraction. In this study, we employed a metaproteomics approach to assess the functional dynamics of the bacteria, fungi, and single-celled parasites residing in the bee gut. Our results describe a dynamic composition of the bacterial community, listing species of relevance to both humans and animals. Bacterial functional concern underlines the vehiculation of virulence and antimicrobial resistance traits. The fungal and single-celled parasite fractions consist of specimens commonly related to the environmental and animal spheres, whose metabolic activities support the role of bees in the diffusion of functional traits across ecological niches. Additionally, the host proteome reflects essential physiological activities of bees, supporting the use of metaproteomics to study multiple microbial species simultaneously and their interactions with the host. Altogether, this study enhances our understanding of the structure and function of the bee gut microbiota, underscoring its potential suitability in addressing various pressing issues such as antimicrobial resistance diffusion, environmental pollution, and the promotion of environmental health.