Dolosigranulum pigrum Cooperation and Competition in Human Nasal Microbiota.

Multiple epidemiological studies identify as a candidate beneficial bacterium based on its positive association with health, including negative associations with nasal/nasopharyngeal colonization by the pathogenic species and Using a multipronged approach to gain new insights into function, we observed phenotypic interactions and predictions of genomic capacity that support the idea of a role for microbe-microbe interactions involving in shaping the composition of human nasal microbiota. We identified community-level and phenotypic cooperation by specific nasal species. Also, inhibited growth , whereas robust inhibition of required both and a nasal together. l-lactic acid production was insufficient to account for these inhibitions. Genomic analysis of 11 strains revealed that has a small genome (average 1.86 Mb) and multiple predicted auxotrophies consistent with relying on its human host and on cocolonizing bacteria for key nutrients. Further, the accessory genome of harbored a diverse repertoire of biosynthetic gene clusters, some of which may have a role in microbe-microbe interactions. These new insights into 's functions advance the field from compositional analysis to genomic and phenotypic experimentation on a potentially beneficial bacterial resident of the human upper respiratory tract and lay the foundation for future animal and clinical experiments. and infections cause significant morbidity and mortality in humans. For both, nasal colonization is a risk factor for infection. Studies of nasal microbiota identify as a benign bacterium present when adults are free of or when children are free of Here, we validated these associations with functional assays. We found that inhibited and, together with a specific nasal species, also inhibited Furthermore, genomic analysis of indicated that it must obtain key nutrients from other nasal bacteria or from humans. These phenotypic interactions support the idea of a role for microbe-microbe interactions in shaping the composition of human nasal microbiota and implicate as a mutualist of humans. These findings support the feasibility of future development of microbe-targeted interventions to reshape nasal microbiota composition to exclude and/or .