Neighborhood plant community, airborne microbiota transferred indoors and prevalence of respiratory diseases are interrelated: A cross-sectional study.

Airborne microbiota transferred indoors (AMTI) is linked to human respiratory health. Yet, the factors influencing these microorganisms and their connections to the prevalence of respiratory diseases (RDs) remain unclear. In this study, we examined plant communities and AMTI using VenTube, next-generation sequencing and quantitative polymerase chain reaction (qPCR) in 72 Shanghai neighborhoods in warm and cold seasons, respectively. To determine the prevalence of RDs, we collected 1026 questionnaires, enlisting 30 ± 5 volunteers aged 40-80, residing in the area for more than a decade, with an equal gender balance. Our results demonstrated that the AMTI communities were less diverse in the cold season than in the warm season, which is in agreement with the changes of garden plant diversity between seasons. Along the reduction of AMTI diversity, greater relative abundances of RDs-associated microbes (e.g., Pseudomonas and Streptococcus) was transferred indoors during the cold season. The questionnaire survey showed that the most prevalent symptom was shortness of breath (25.6 %), followed by rhinitis (20.8 %) and wheeze (14.4 %), with generally no prevalence difference between urban and peri-urban neighborhoods. Notably, despite the sparse garden plant community in the cold season, the abundance of Oleaceae trees showed an inverse relationship with the RDs-associated microbes as well as the prevalences of RDs based on the structural equation model results. This finding was largely supported by the negative effect of Oleaceae trees on the population of Streptococcus anginosus (qPCR) which was a dominant species transferred indoors in the cold season, given that S. anginosus is highly associated with rhinitis and rhinoconjunctivitis. Taken together, our findings suggest a strong association between the Oleaceae trees, the AMTI and the prevalence of RDs, which can shed some lights in the ecological development towards respiratory safe environment in cities.