Preliminary Studies on the Pollution Levels of Antibiotic Resistance Genes in the Water of Beijiang River,South China

The bacterial resistance and antibiotic resistance genes (ARGs)among 9 water samples along Beijiang River, South China, were investigated in this work. Culture -based approach was used for the resistance level checks of three classes of antibiotics including tetracycline (TET), macrolides (ERY)and sulfonamides (SMT). Polymerase chain reaction (PCR)assay were applied to detect the presence/absence of two sulfonamide ARGs (sul1 and sul2). It was found that 8 samples were resistant to TET, 5 to ERY and 7 to SMT, respectively. Five samples with sul1 and four samples with sul2 were found in the samples using PCR assay and gene sequence confirmation. Moreover, it was obtained that the ratios of copy values of sul1 or sul2 to 16S-rRNA, reflecting the ARG pollution level, ranged from 10-2.56 to 10-0.52 and 10-3.25 to 10 -1.24, respectively, in the seven water samples. The levels of ARGs were much higher than those obtained in the water samples from Northern Colorado River. Also, it was found that the ratios of ARGs had good correlation to the concentrations of the selected SMTs occurred in water samples in Beijiang River.