The environment shapes swine lung bacterial communities

Previous studies of the lung microbiome have focused on characterizing the community and attempts to understand the role of community membership concerning disease or exposures such as cigarette smoke. However, we still lack an understanding of two critical aspects of the lung microbiome: the origin of the community members and their fate. As we continue to better understand how the lung microbiome influences human health, it is essential to determine how the environment shapes the lung microbiome membership. Using a pig model, we explored the relationship that the surrounding environment has on the resident lung bacteria by collecting environmental samples (soil, air, water, feed) to compare with lung samples (swab, lavage, and tissue). Results suggest that airborne bacteria make up the highest portion of the lung microbiome. Furthermore, bacteria from samples taken from the bronchioles can be correctly identified by which farm they originated, whereas those from alveolar samples are indistinguishable. The findings suggest that while the environment may shape the microbiome of the bronchioles, a distinct community exists within the alveoli. Our findings expand upon the current understanding of the lung microbiome and provide a model of how microbial communities within the lung relate to their surrounding environment. • Most bacteria found in the bronchioles can be sourced from local ambient air. • There are differences between lung alveolar and bronchiolar microbiomes. • The environment influences bacteria found at the bronchiolar level but not alveolar.