Figure 1.

Relative abundance [copies of antimicrobial resistance genes (ARG)/copies of 16S-rRNA] of sulfonamide resistance genes. a) sul1 and b) sul2. Error bars represent standard deviation of the mean. A — feedlot A, B — feedlot B, C — feedlot C, DC — feedlot D (conventional production), DN — feedlot D (natural production), CB — catch basin, Influent — sewage influent, Effluent — sewage effluent, and Creek — Ephemeral creek.

^{a,b,c,d,e,f,g} Different letters represent significant difference (P ≤ 0.05).