Taxonomic composition of subway microbial communities. Taxonomic composition of subway microbial communities. All ordinations are from principal coordinate analyses using Bray-Curtis distances among filtered OTUs (see Materials and Methods), colored by metadata. (A) Subway data by surface. PC1, principal coordinate 1; PC2, principal coordinate 2. (B) Train car data by train line. (C) Touchscreen data by location of machine. (D) Relative abundances of bacterial families across samples from train cars (see Table S2 in the supplemental material for complete data). (E) Relative abundances of bacterial families within stations (complete data determined as described above). Stars indicate that the sample was collected on a separate day during the same month as the remaining samples. For station samples, “W” indicates a sample from a ticketing machine wall; all other samples were from the ticketing machine touchscreens. Tiffany Hsu et al. mSystems 2016; doi:10.1128/mSystems.00018-16