Bacteria bacterium 6 classification microbiology 6 Humans 5 human 5 genetics 4 isolation and purification 4 Article 3 RNA 16S 3 microflora 3 nonhuman 3 Adult 2 Animals 2 Case-Control Studies 2 Feces 2 Female 2 Gastrointestinal Microbiome 2 Hydrogen-Ion Concentration 2 Male 2 Microbiota 2 Middle Aged 2 RNA, Ribosomal, 16S 2 adult 2 animal 2 case control study 2 complication 2 controlled study 2 feces 2 female 2