Reducing skin microbiome exposure impacts through swine farm biosecurity

Background: Livestock work is unique due to worker exposure to animal-associated microbiomes within the workplace. Swine workers are a unique cohort within the US livestock labor force, as they have direct daily contact with pigs and undertake mandatory biosecurity interventions. However, investigating this occupational cohort is challenging, particularly within tightly regulated commercial swine operations. Thus, little is known about the impacts of animal exposure and biosecurity protocols on the swine worker microbiome. We obtained unique samples from US swine workers, using a longitudinal study design to investigate temporal microbiome dynamics. Results: We observed a significant increase in bacterial DNA load on worker skin during the workday, with concurrent changes in the composition and abundance of microbial taxa, resistance genes, and mobile genetic elements. However, mandatory showering at the end of the workday partially returned the skin's microbiome and resistome to their original state. Conclusions: These novel results from a human cohort demonstrate that existing biosecurity practices can ameliorate work-associated microbiome impacts.