Impact of environmental microbiota on human microbiota of workers in academic mouse research facilities

Project Description: We performed area air sampling from the animal rooms, dirty, middle, and setup cage wash locations in four academic mouse research facilities. 10 workers in the dirty cage wash area underwent personal air sampling as well as serial collection of nasal, oral wash, and skin samples before and after the work shift. Environmental samples underwent measurements of endotoxin, mouse allergen, bacteria copy number via 16S qPCR, and microbial identification via 16S rDNA sequencing. 16S rDNA sequencing was also performed on human samples before and after the work shift. Median endotoxin levels ranged from undetectable to 1.0 EU/m3. Significant differences in mouse allergen levels, bacterial copy number, microbial richness, and microbial community structure were identified between animal, dirty, middle, and setup cage wash locations. Endotoxin levels had only a moderate correlation with microbial composition. Location within a facility was a stronger predictor of microbial community composition (R2 = 0.41, p = 0.002) than facility. 33 taxa in the oral microbiome and 44 taxa in the skin microbiome of workers differed when comparing pre- vs. post-shift samples. The microbial environment of academic animal care facilities varies significantly by location; these differences are not well approximated with measurement of endotoxin levels. We find evidence that the oral and skin microbiome of workers in dirty cage wash areas change during the course of their work shift.