Antibiotic-resistant bacteria pose a significant threat to public health worldwide. This study investigated how human activities impact antibiotic resistance genes in three locations along the River Berettyó in Hungary. The study found that population density has an impact on antibiotic-resistant genes. The bacteria Escherichia coli and Klebsiella pneumoniae were identified in the samples. The study found 17 plasmids containing blaCTX-Ms in the bacteria, which are resistant to antimicrobial drugs and linked to community and hospital-acquired infections. The study is the first to report different blaCTX-Ms in the eastern part of Hungary.