Bee Microbiomes Harbor Diverse Antimicrobial Resistance Genes on Plasmids

Antimicrobial resistance (AMR) is an emerging public health threat. In North America, tetracycline and macrolide antibiotics are often used to prevent or treat bacterial infections in honey bees. Previous research has shown that this practice has led to widespread drug resistance in honey bee gut microbiomes. However, where bee-associated bacteria encode AMR, genomically or on mobile genetic elements, is less well understood. Moreover, how the abundance, diversity, and mechanism of AMR differs between managed honey bees and other bees remains largely unexplored. Here we use existing metagenomic data from two previous studies to profile the AMR genes associated with managed honey bees, commercially produced bumble bees, and wild bumble bees. Our results suggest that honey bee associated bacteria house a greater diversity of AMR genes, specifically on plasmids, compared to bumble bees. In addition, we show that honey and bumble bee bacteria likely develop resistance to tetracyclines via different mechanisms. Overall, this study showcases how agricultural management has shaped the AMR genes associated with bees, and offers insights into the ecological context of differential AMR evolution within host-associated systems.