Figure 7. Comparison of the prevalence of antibiotic-resistant bacteria on SCD agar plates with that on MacConkey agar plates, and identification of representative antibiotic-resistant Enterobacterales, including MIC data.

(A) Antimicrobial susceptibility testing results for each of the isolates (MIC₅₀ and MIC₉₀) for six antimicrobial agents (AMP, KAN, TET, CHL, CIP, and SPY). Isolates were tested using the agar-dilution method on Muller-Hinton II agar medium (BD Biosciences) according to the criteria determined by the CLSI (Wiegand, Hilpert & Hancock, 2008). (B) Cluster analysis based on MIC data. The identified bacteria derived from the “River: Shinoroshinkawa” site formed a distinct cluster and had higher MIC values than isolates obtained from other locations. Yellow coloring indicates MIC values for isolates derived from “River: Shinoroshinkawa”.