Fecal-associated microbiome differences between phlegm-dampness constitution and balanced constitution

Objective: This study aimed to explore the structural and functional characteristics of the fecalassociated microbiome（FAM） between the phlegm-dampness constitution（PDC） and balanced constitution（BC）, and to screen the related specific operational taxonomic unit（OTU） biomarkers.Methods: This was a cross-sectional study. After strictly identifying the constitution of subjects, their clinical index was recorded and counted. Fecal samples were collected for 16S rDNA sequencing. Alpha diversity, beta diversity, and the relative abundance of dominant bacterial taxa were used to describe the FAM structure, and the Wilcoxon rank-sum test, Metagenome Seq, and linear discriminant analysis effect size（LEf Se） were used to screen specific bacterial taxa. Specific OTUs were screened to construct receiver operating characteristic（ROC） curves.Results: Thirty-two subjects were enrolled, including 22 subjects with BC and 10 subjects with PDC.There were significant differences in cold preference, levels of aspartate transaminase, β2-microglobulin,and creatine kinase MB, and alpha diversity indices（Shannon and Shannoneven） between the two groups. In principal coordinate analysis by abund-jaccard distance measure and partial least squares discriminant analysis, bacterial communities clustered separately between the two groups. Furthermore,based on Metagenome Seq, LEf Se, and the Wilcoxon rank-sum test, a total of 43, 18, and 130 OTUs were differentially distributed between BC group and PDC group, respectively, and OTU200, OTU133, and OTU353 were screened when P≤.01. The area under the ROC curve constructed from the 3 selected OTUs was 0.93.Conclusion: The FAM structure and related functional characteristics of the PDC group differed from those of the BC group. In particular, OTU200, OTU133, and OTU353 can be used as unique markers of PDC to assist clinical diagnosis.