host-associated 2,123 animal host 2,123 mammalian host 1,874 human host 1,752 industrialized 1,594 digestive tract 1,265 adult 814 skin 799 mouth 756 intestine 733 elderly 592 saliva 433 anthropogenic 251 urban 229 terrestrial 220 built environment 217 child 170 airways 90 hospital 54 infant 52 urogenital tract 41 adolescent 39 preterm birth 37 agriculture 23 rural 22 non-industrialized 16 soil 15 aquatic 8 wastewater 7 traditional agriculturalist 4 cropland 4 full term birth 2 ancient microbiome 2 medium temperature 2 ancient dental calculus 2 negative control 2 anaerobic 2 sludge 2 sewage 1 plant host 1 paludal 1 marine 1 lentic 1 high salinity 1 wetland 1