terrestrial 1,087 anthropogenic 879 aquatic 592 built environment 563 host-associated 490 soil 350 animal host 331 digestive tract 215 intestine 213 wastewater 209 mammalian host 196 plant host 162 sludge 160 fresh water 153 marine 126 rhizosphere 119 human host 117 lentic 106 agriculture 101 low salinity 99 hospital 85 industrialized 82 benthic 73 insect host 67 sediment 64 lacustrine 63 subsurface 60 groundwater 53 contaminated 52 elderly 47 very low temperature 46 high salinity 40 skin 38 sewage 38 paludal 35 wetland 35 forest 30 ice 27 medium temperature 26 cropland 23 pelagic 23 adult 22 medium salinity 20 estuary 19 alkaline 19 brackish water 19 mine 17 arid 14 phyllosphere 14 very high salinity 13 littoral 13 infant 13 permafrost 12 plant litter 11 lake bed 11 grassland 11 sea floor 10 low temperature 10 food 10 lotic 10 stream 10 spring 10 preterm birth 9 saline water 9 acidic 9 very high temperature 8 hydrothermal vent 8 dairy product 6 anaerobic 6 briny water 5 tundra 5 urban 4 fermented food 4 waste 3 child 3 coral reef 3 traditional agriculturalist 2 rural 2 saliva 2 non-industrialized 2 mouth 2 hot spring 2 airways 2 high temperature 1 stream bed 1 air 1 fluvial 1 rumen 1