host-associated 1,733 animal host 1,730 mammalian host 1,682 human host 1,680 industrialized 1,471 skin 1,385 anthropogenic 1,291 built environment 1,284 terrestrial 1,271 adult 636 elderly 512 intestine 341 digestive tract 341 infant 304 hospital 218 preterm birth 178 urban 83 airways 42 aquatic 18 full term birth 15 saliva 11 mouth 11 very low temperature 7 fresh water 6 ice 6 marine 6 low salinity 5 high salinity 4 lacustrine 3 lentic 3 negative control 3 plant host 3 groundwater 3 subsurface 3 phyllosphere 2 urogenital tract 2 rural 2 child 2 adolescent 2 non-industrialized 2 rhizosphere 1 arid 1 traditional agriculturalist 1 alkaline 1 pelagic 1