part of occurs in microbial population phenotype in host has microbe expanded in diseased host has participant located in has disease rheumatoid arthritis Bacteroides sp. Prevotella Homo sapiens RA human-gut microbiome interaction increased organism quantity compared with healthy control segregation of Prevotella or Bacteroides dominance in RA human gut Haihe Wang, Yongqun He https://www.ncbi.nlm.nih.gov/pubmed/24192039 a RA human-gut microbiome interaction that shows high Prevotella or high Bacteroides relative abundance, but rarely a high relative abundance of both. lower digestive tract