Derived ecological niches of indoor microbes are crucial for asthma symptoms in university dormitories

Increasing evidences from home environment indicate that microbiome community is associated with asthma. However, indoor microbiome composition can be highly diverse and dynamic, and thus current studies fail to produce consistent association. Chinese university dormitories are special high-density dwellings with a standard built environment and personal characteristics for occupants, which can be used to disentangle the complex interactions between microbes, environmental characteristics and asthma. Settled air dust and floor dust was collected from 87 dormitory rooms in Shanxi University. Bacterial community was characterized by 16S rRNA amplicon sequencing. Students (n = 357) were surveyed for asthma symptoms. Asthma symptoms were not associated with the overall bacterial richness, but associated with different phylogenetic classes. Taxa richness and abundance in Clostridia and Bacteroidia were positively associated with asthma (p < 0.05), and these taxa were mainly derived from human gut. Taxa richness (p < 0.1) and abundance (p < 0.05) in Alphaproteobacteria and Actinobacteria were protectively associated with asthma, and these taxa were mainly derived from outdoor environment. Building age, floor and curtain cleaning frequency shaped the overall bacterial community of air dust (p < 0.05). Frequent curtain cleaning increased the relative abundance of 10 protective genera (p < 0.05), and old buildings had mix effects to protective genera (p < 0.05). Our data shows that taxa from different phylogenetic classes and ecological niches have different health effects, indicating the importance of incorporating evolutionary and ecological concepts in revealing general patterns in the microbiome asthma association analysis.