host-associated 7,142 animal host 7,141 digestive tract 7,137 mammalian host 6,889 intestine 6,792 human host 5,244 industrialized 4,043 adult 2,115 child 776 infant 632 rural 622 non-industrialized 586 urban 559 mouth 407 elderly 405 saliva 295 adolescent 173 rumen 144 aquatic 90 full term birth 78 anthropogenic 52 traditional agriculturalist 50 terrestrial 49 hunter-gatherer 47 airways 44 fresh water 37 preterm birth 34 wastewater 31 low salinity 27 agriculture 17 sewage 16 groundwater 16 subsurface 16 soil 14 contaminated 13 marine 12 lentic 12 lacustrine 11 ancient microbiome 10 sludge 10 medium temperature 7 built environment 6 benthic 6 sediment 6 mine 5 insect host 5 stream 4 hospital 4 cropland 4 anaerobic 4 tundra 4 alkaline 2 low temperature 2 lake bed 2 very low temperature 2 waste 2 ice 2 plant host 1 acidic 1 fermented food 1 wetland 1 food 1 phyllosphere 1 permafrost 1 paludal 1 urogenital tract 1 high salinity 1