Study: swine workers' microbiomes change through the day; personal air samples track most closely

Dr. Noelle Noyes of the University of Minnesota described a seven-day longitudinal study of 40 swine farm workers across seven Midwestern farms, sampling nasal, hand and armpit/elbow sites four times daily. She reported that bacterial load and diversity rose during the workday and declined after workers showered out: "when they come in in the morning, they have this certain bacterial load… that then increases by the lunch break… and then showering decreases that load back down closer to baseline."

Noyes emphasized that genus-level overlaps do not prove transmission; finer-resolution genomics are needed to confirm strain sharing. In a paired environmental sampling day, personal air samplers worn by workers showed the greatest overlap with worker samples, while pig-derived samples had fewer shared bacteria, leading Noyes to conclude that airborne bioaerosols are a primary vector for worker microbiome change in these settings. She noted the study excluded individuals with recent antibiotic use and that survey metadata on hand hygiene and glove use remain under analysis.

The presentation highlighted practical implications for biosecurity and surveillance in agricultural settings: worker microbiomes are dynamic across a single workday, and sampling timing matters for interpretation. Noyes said the team is analyzing how personal protective equipment and specific work tasks influence microbiome sharing between environment, animals and workers.