Antimicrobial Resistance Genes (ARGs) Monitoring and Gut Microbiota Profiling in Honey Bees from an Intensive Livestock Farming Area

Antimicrobial resistance (AMR) is a growing global concern, exacerbated by the overuse of antibiotics in livestock farming. Honey bees (Apis mellifera), widely used as bioindicators of environmental contamination, may also serve as sentinels for monitoring the environmental spread of antibiotic resistance genes (ARGs). This study investigated the presence of ARGs and the gut microbiota composition of honey bees sampled from 11 apiaries located in a region of Northwestern Italy characterized by intensive livestock farming. PCR and sequencing analyses revealed a widespread presence of tetracycline resistance genes—particularly tet(B) and tet(C)—as well as occasional detection of blaTEM, qnrB, and int1 genes. ARGs were also identified in bacterial colonies isolated from bee guts, notably in Hafnia spp. 16S rRNA gene sequencing of the gut microbiota revealed dominance of genera such as Bartonella, Snodgrassella, Gilliamella, Bombilactobacillus and Lactobacillus. Some samples showed reduced microbial diversity or shifts associated with possible dysbiosis. The findings confirm the potential of honey bees as bioindicators for environmental AMR surveillance and underscore the need for further research to elucidate correlations between ARGs presence and microbial community structure in honey bees from various ecological contexts.