D3196: Probiotics composed of native gut bacteria reduce the deleterious effects of microbiota perturbation in honey bees

Honey bee guts contain a distinct microbiome with core bacterial lineages that are highly host-specific. This microbiota has been shown to provide diverse benefits including stimulating developmental and metabolic processes, activating host immunity, processing food, and protecting against pathogens. However, honey bees, in their current role as agricultural pollinators, are exposed to numerous compounds that can disrupt their gut microbiota. Examples of these chemical insults include antibiotics for the treatment of foulbrood and incidental exposure to herbicides. To date, most work with honey bee probiotics has involved bacterial isolates that are not native to the bee gut including strains that are used in human food production. We found that probiotics consisting of co-cultured isolates from the native bee gut microbiota may be introduced to microbiota-deficient bees in which they establish at levels similar to normal gut communities. We demonstrate that bees inoculated with these native bacteria are less prone to colonization by opportunistic pathogens. Antibiotic treatment of hives at recommended levels causes microbiota disruption and heightened mortality following pathogen challenge. We found that probiotic treatment of bees from antibiotic-treated hives reduces the impact of this disruption, resulting in less susceptibility to pathogens. Recent work from our lab reveals that many of these cultured strains can engraft in the guts of bees with established microbiota after those communities have been destabilized with antibiotics. Taken together, this research shows that probiotic treatment with native gut strains may help destabilized colonies to reinstate the benefits of their bacterial partners.