Effects Of Environmental Factors On Microbial Diversity And Community Structure In Nasopharynx

ObjectiveTo explore the impact of environmental factors such as common atmospheric pollutants and meteorological factors on the diversity and community structure of the nasopharyngeal microbiome(NPM)in healthy people and asthma patients,and provide scientific evidence for the prevention and treatment of respiratory diseases.MethodsThis study was divided into two parts.The first part was to explore the relationship between environmental factors and NPM in healthy young people,and the second one was to illustrate the effects of environmental factors on NPM in asthmatic adults.(1)Nasopharyngeal swabs and questionnaires of healthy individuals were collected from college students at Zhengzhou University.The samples obtained in March 2018 were named as spring group(S),and the samples taken in September 2018 were named as fall group(F).A total of 16 matched nasopharyngeal samples were included(8 in group S,8 in group F).(2)Nasopharyngeal swabs and questionnaires of asthmatic adults were sampled at the respiratory clinic of the First Affiliated Hospital of Zhengzhou University.The samples collected from January to March 2018 were named as spring/winter group ?(W1),and the samples collected from January to March 2019 were named as spring/winter group ?(W2).A total of 22 nasopharyngeal samples of asthmatic adults were included(9 in the W1 group,13 in the W2 group).All the data of environmental factors(including PM2.5,SO2,NO2,O3,T,H)on the day of sampling(D0),7 days before sampling(D7),and a month before sampling(M),was collected.The total DNA was extracted from the NPM,and the V3-V4 region of 16S rDNA of NPM was amplified and sequenced by high-throughput sequencing platform Illumina Miseq.The sequences information was processed using QIIME software,and the nasopharyngeal microbial composition,diversity and community structure,and their association with various environmental factors were analyzed by R software and SPSS statistical software.Results1.There was a significant difference in ? diversity between the NPM in group S and F(P--0.04),and there was no significant change in a diversity(P>0.05).The core microbiome of the nasopharynx in healthy youth were Streptococcus,Neisseria,Haemophilus,Porphyromonas,Prevotella and Fusobacterium.2.Difference analysis shown that the abundances of Acidobacteria,Gemmatimonadetes,and Symbiobacterium in the NPM in group S were significantly higher than those in group F,while Streptococcus,Prevotella,and[Prevotella]were enriched in group F.RDA analysis indicated that PM2.5 and air temperature(T)were the main environmental factors affecting the community structure of nasopharynx in group S and F.Correlation analysis shown that the Acidobacteria,Gemmatimonadetes,and Symbiobacterium exhibited significant positive correlations with PM2.5,the genera Streptococcus,Prevotella,and[Prevotella]were positively correlated with T.3.There was a significant difference in a diversity between the NPM in the group W1 and W2(P<0.05),and there was also a significant difference in ? diversity(P=0.001).There was no significant difference in a and ? diversity in different states of asthma(P>0.05).The core microbiome of asthmatic adults was Streptococcus,Neisseria,Prevotella,Fusobacterium,Haemophilus,Granulicatella,and Veillonella.4.Difference analysis has shown that the abundances of Streptococcus,[Prevotella],Haemophilus,and Actinobacillus in group W1 were significantly higher than those in group W2,while Rothia,Thermus,Actinomyces,Fusobacterium,Cupriavidus,Leptotrichia,and Acinetobacter were enriched in group W2.PLS-DA analysis indicated that Streptococcus,Rothia,Actinomyces,and Thermus were the four genera with the greatest impacts on community structure.RDA analysis indicated that PM2.5 and air temperature(T)were the main environmental factors affecting the community structure of nasopharynx in group W1 and W2.Correlation analysis has shown that the Rothia,Thermus,and Actinomyces exhibited significant positive correlations with NO2 and negative correlations with O3,the genera Streptococcus was negatively correlated with NO2 and positively correlated with O3.5.RDA analysis has shown that environmental factors have synergistic and antagonistic effects on the community structure of the NPM.Correlation analysis found that the environmental factors one month before sampling(M)were associated with more NPM,and their impacts on NPM were greater than the environmental factors on the day of sampling(D0)and seven days before sampling(D7).It was suggested that the influence of environmental factors on NPM may have a lag effect.6.The a diversity of NPM in asthmatic adults was higher than that in healthy individuals(P=0.014),but there was no difference in ? diversity(P=0.143).The genera Granulicatella,Veillonella may be associated with asthma.Conclusions1.Changes in environmental factors between different seasons can significantly alter the composition,diversity and community structure of NPM in healthy individuals and asthmatic adults.2.Between spring and autumn,PM2.5 and T are the main environmental factors affecting the community structure of NPM in healthy individuals,and are significantly related to specific bacteria.3.In spring/winter,NO2 and O3 are the main environmental factors affecting the diversity and community structure of NPM in asthmatic adults,and are significantly related to specific bacteria.4.The influence of environmental factors on the diversity and community structure of NPM may be caused by the synergy or antagonism of multiple environmental factors on the flora.