Impact of environmental microbiota on human microbiota of workers in academic mouse research facilities: An observational study.
Lai PS, Allen JG, Hutchinson DS, Ajami NJ, Petrosino JF, Winters T, Hug C, Wartenberg GR, Vallarino J, Christiani DC
PLoS One. 2017. doi: 10.1371/journal.pone.0180969
COMMENT: High level microbial exposures are common in many work settings and linked to health effects. The objective of this work was to determine whether the work microbiome contributes to the human microbiome of workers in academic mouse research facilities.
The authors 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 repeated collection of nasal, oral, and skin samples before and after the work shift. Environmental samples underwent measurement 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. SourceTracker was used to identify the contribution of the work microbiome to the human microbiome.
The authors demonstrates that there are 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.
Finally the authors conclude that the microbial structure of academic animal care facilities varies significantly by location rather than by individual facility; these differences are not well approximated with measurement of endotoxin levels, limiting our ability to extrapolate from prior occupational studies relying only on endotoxin for exposure assessment.
They found evidence that a non-zero proportion of the nasal and skin microbiome of workers can be traced to their work environment as a source. This opens up the possibility that work-related microbes may impact health through a mechanism other than microbial toxin exposure.
The authors suggest that further research on the long-term stability of changes in the adult human microbiome due to occupational microbial exposure, the factors that impact susceptibility to colonization by microbes in the work environment, and the health effects of the workplace microbiome, should be considered. This approach could change how we set safe microbial work exposure standards in the future.