Spearman correlation matrix of the percent resistances to the eight drugs in seven of the nine sampling sites.

The sites of Haizi reservoir and Cuo River upstream have been removed based on the low antibiotic levels and few E. coli isolates, respectively. AMP = ampicillin, C = chloromycetin, LEV = levofloxacin, TE = tetracycline, CN = gentamycin, SXT = sulfamethoxazole-trimethoprim, SMM = sulfamonomethoxine, CTC = chlortetracycline). ** indicate the significance level of pSpearman correlation matrix of the percent resistances to the eight drugs in seven of the nine sampling sites.