Quantification of antibiotic resistance marker and virulence factor abundances on subway surfaces. Quantification of antibiotic resistance marker and virulence factor abundances on subway surfaces. (A) Antimicrobial resistance markers (rows) quantified in metagenomes by ShortBRED (36) and annotated by antibiotic target through the use of antibiotic resistance ontology in CARD. (B) Virulence factors (rows) likewise quantified and manually annotated by virulence function through the use of keywords on the VFDB website. For both heat maps, columns (samples) are arranged as described for Fig. 6. Tiffany Hsu et al. mSystems 2016; doi:10.1128/mSystems.00018-16