Investigating the effects of a common apiculture antibiotic on honeybee colonies and prevalence of antibiotic resistance

Antibiotic overuse in livestock management is hypothesized to contribute to the spread of antibiotic resistance. During the management of Western honeybee (Apis mellifera) populations for the commercial pollination of agricultural crops and honey production, beekeepers use antibiotics to prophylactically prevent or treat bacterial diseases in their colonies. However, decades of off-label use in beekeeping led to several legislative actions to reduce the profession’s misuse of antibiotics. Nevertheless, it remains unclear whether federally approved treatment regimens realistically perturb whole colonies and increase the spread of antibiotic resistance as suggested in lab-based studies in the literature. We therefore aimed to investigate the effects of oxytetracycline treatment on honeybee colonies and the prevalence of antibiotic resistance in a field-realistic setting. We hypothesized that colony-level, federally approved prophylactic oxytetracycline treatment would negatively influence colony health and increase resistance prevalence in worker guts. To test this hypothesis, we treated whole honeybee colonies following federal guidance and measured several colony health metrics before, during, and after treatment between May and October 2024. This study was done in collaboration with a local Wisconsin beekeeper and funded by a USDA Sustainable Agriculture and Education Research grant. Preliminary results indicate that prophylactic antibiotic treatment may be beneficial to long-term colony health, as treated colonies produced more honey and workers and collected more pollen compared to control colonies. The full results of this study will provide critical, nuanced insight into the risks associated with antibiotic use in livestock management and have broad implications for the future of apiculture.