Nasal microbiota composition dynamics after occupational change in animal farmers suggest major shifts

Previous studies have suggested a significantly higher diversity of pig farmers' nasal microbiota compared to the nasal microbiota of people having no contact with farm animals. Moreover, specific pig associated bacterial sequence variants were observed in the nasal cavities of pig farmers. However, the fate of this nasal microbiota specificity, after farmers stop being in contact with the pig farm environment, is unknown. Therefore, the aim of this study was to investigate the change of pig farmers' nasal microbiota after the change of occupation. Methods: Nasal swabs from seven pig farmers were collected and new samples were taken after a period of at least 50 days after having left the pig farm. Illumina MiSeq sequencing was conducted on the extracted DNA to characterize the nasal microbiota. Microbiota composition of pig farmers and ex-pig farmers were received and compared with microbiota of controls (cow farmers and non-exposed individuals).Results: Following the period after pig exposure, richness and SDI of both anterior and posterior cavities dropped significantly. The composition of the microbiota of, pig farmers had the lowest similarity with the non-exposed group while ex-pig farmers were more similar to cow farmers and the non-exposed group than to their previous own microbiota. Conclusion: The pig farmer's microbiota composition specificity is not permanent. The nasal microbiota of ex-pig farmers no longer showed the specificities of a regular pig farmer's microbiota and became either more similar to the microbiota of the non-exposed group or the microbiota of cow farmers.