A longitudinal field study of commercial honey bees shows that non-native probiotics do not rescue antibiotic treatment, and are generally not beneficial

Authors: Anderson, Kirk; ALLEN, N. - University Of Arizona; Copeland, Duan; KORTENKAMP, O. - University Of Arizona; Erickson, Robert; Mott, Brendon; OLIVER, E. - Scientific Beekeeping

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/14/2024
Publication Date: 1/23/2024
Citation: Anderson, K.E., Allen, N., Copeland, D.C., Kortenkamp, O., Erickson, R.J., Mott, B.M., Oliver, E. 2024. A longitudinal field study of commercial honey bees shows that non-native probiotics do not rescue antibiotic treatment, and are generally not beneficial. Scientific Reports. 14. Article 1954. https://doi.org/10.1038/s41598-024-52118-z.
DOI: https://doi.org/10.1038/s41598-024-52118-z

Interpretive Summary: The collection of bacteria in the honey bee gut (microbiome) provides major contributions to host health, and changes in the size or structure of the gut bacterial community (dysbiosis) can be detrimental to host function. Antibiotic treatments can greatly distort the microbiome, reducing its protective abilities and facilitating the growth of antibiotic resistant core bacteria or pathogens. Probiotics are often suggested as a remedy to ease gut dysbiosis but there is little evidence that probiotics are effective. Commercial beekeepers regularly apply antibiotics to combat bacterial infections, often followed by an application of probiotics advertised to ease the impact of antibiotic-induced gut dysbiosis. Here, the effects of antibiotic exposure and probiotic rescue on the size and composition of the honeybee gut microbiome were examined. Colony metrics were monitored throughout the experiment to determine if antibiotic induced gut dysbiosis impacts colony growth, and whether probiotic application improves the gut microbiome or rescues the negative effects of antibiotic induced dysbiosis. The introduced probiotic strains in the gut microbiome could not be detected, and no difference in the gut microbiome by probiotic application or antibiotic recovery associated with probiotic treatment could be found. Our results show that a colony-level application of the antibiotics oxytetracycline and tylosin produce an immediate decrease in gut microbiome size, and over the longer-term, produce very different and persistent dysbiotic effects on the composition of the hindgut microbiome. Our results demonstrate the lack of probiotic effect or antibiotic rescue, detail the dysbiotic states resulting from different antibiotics and highlight the importance of the gut microbiome for honeybee health.

Technical Abstract: The collection of bacteria in the honey bee gut (microbiome) provides major contributions to host health, and changes in the size or structure of the gut bacterial community (dysbiosis) can be detrimental to host function. Antibiotic treatments can greatly distort the microbiome, reducing its protective abilities and facilitating the growth of antibiotic resistant core bacteria or pathogens. Probiotics are often suggested as a remedy to ease gut dysbiosis but there is little evidence that probiotics are effective. Commercial beekeepers regularly apply antibiotics to combat bacterial infections, often followed by an application of probiotics advertised to ease the impact of antibiotic-induced gut dysbiosis. Here, we examined the effects of antibiotic exposure and probiotic rescue on the size and composition of the honeybee gut microbiome. Colony metrics throughout the experiment were monitored to determine if antibiotic induced gut dysbiosis impacts colony growth, and whether probiotic application improves the gut microbiome or rescues the negative effects of antibiotic induced dysbiosis. The introduced probiotic strains in the gut microbiome could not be detected, and no difference in the gut microbiome by probiotic application or antibiotic recovery associated with probiotic treatment could be found. Our results show that a colony-level application of the antibiotics oxytetracycline and tylosin produce an immediate decrease in gut microbiome size, and over the longer-term, produce very different and persistent dysbiotic effects on the composition of the hindgut microbiome. Our results demonstrate the lack of probiotic effect or antibiotic rescue, detail the dysbiotic states resulting from different antibiotics and highlight the importance of the gut microbiome for honeybee health.