Cumulative Characteristics And Interrelationships Of Dust Mites And Bacteria In Residential Areas

Dust is a complex,multi-phase mixture of particles that is heterogeneous,has a wide range of sources(such as soil,atmospheric deposition of particles and wear and tear off of household materials)and a complex chemical composition,which is a major carrier of dust mite allergens and bacteria.Dust mite allergens are an important cause of allergic diseases such as asthma,rhinitis and eczema.Bacteria and their metabolites may contaminate the environment in residential areas.Indoor and public areas in residential housing are the main living places for humans,and the dust and loads in these areas are of great relevance to human health.Therefore,it is of interest to explore the interaction between dust mite allergens and bacterial communities in residential indoor and public area dust.This study took residential areas in Changchun city as the research object,mainly collecting two different types of dust(particulate matter and flocculent fibrous)in residential areas,and collecting particles dust in public areas(stairs,elevators,parking lots,supermarkets,express stations,and squares)to explore the concentration distribution characteristics of dust mite allergens(including Dermatophagoides pteronyssinus(Der p1)and Dermatophagoides farinae(Der f 1))in dust and the factors affecting their concentration levels.Meanwhile,the differences in bacterial community composition and diversity in different types and functional areas of dust were analyzed by high-throughput sequencing,and the interactions between Der p 1,Der f 1 and bacterial communities were further explored.Among residential indoor dusts,Der p 1 and Der f 1 tended to accumulate more in flocculent fibrous dusts,with Der p 1 dominating the residential indoor dust samples in Changchun.Floor height,building age and living area all significantly influenced the concentration of dust mite allergens in indoor dust in dwellings(p < 0.05).Actinobacteria,Proteobacteria,and Firmicutes were the dominant bacteria of the two types of dust.Kocuria,Blastococcus and Massilia were the main genera in particulate IV dust,while Acinetobacter,Lactobacillus and Corynebacterium＿1 were the main genera in flocculent fibrous dust.The diversity and abundance of bacterial communities in particulate dust was significantly higher than in flocculent fibrous dust(p < 0.01).The living area was an important factor influencing the bacterial community in flocculent fibrous dust(p < 0.01).The concentration of Der f 1(12.44 ng/g)was higher than Der p 1(6.78 ng/g)in dust in the residential common areas and the concentration of dust mite allergens was higher in Lvyuan district compared to other districts.Public areas were more susceptible to environmental factors than residential indoor areas.Among these,temperature and relative humidity were important influences on dust mite allergen concentrations in public areas,both of which were positively correlated with house dust mites(HDMs).Also,floor height,type of functional area,building age,areas of the region and distance from the street all had a significant effect on the concentration of HDMs(p < 0.05).The dominant phyla in the dust bacterial community in residential public areas were Actinobacteria,Proteobacteria and Firmicutes.Bacterial communities in dust from different functional areas showed variability at the genus level.For example,the relative abundance of genus Pseudonocardia(23.41% ± 14.41%)was high in the parking lot and low in other areas.Potentially pathogenic genera(genus Blastococcus and genus Kocuria)were also found in stairs,supermarkets,express stations and squares.The squares had relatively better ventilation and mobility and exhibited a high bacterial community richness and diversity.The parking lot showed a significantly different bacterial community composition from the other functional areas due to the high level of contamination.Temperature,humidity,different functional areas,building age,areas of the region,distance from factories and streets all significantly influenced the variation in bacterial community composition in common area dust(p < 0.05).Bacteria can act as food as well as establish a symbiotic relationship with HDMs hosts and provide nutrition.However,the relationship between the relative abundance of bacteria and dust mite allergen concentrations varied considerably due to the different sources and chemical composition of dust from different types and functional areas.For example,the interaction between Proteobacteria,Firmicutes and HDMs in residential indoor areas varies considerably between different types of dust.In the common areas,only the growth relationship between the phylum Proteobacteria and HDMs was significantly positively correlated.Exploring the interaction of HDMs and bacteria in different types and functional areas of dust will lead to more precise prevention and treatment strategies for patients with allergic diseases in different living situations.