Key Findings

The study identified various antibiotic resistance genes (ARGs) in river biofilms upstream and downstream of a wastewater treatment plant (WWTP), including qnrA, qnrS, mfsA, ermC, ermX, macB, mefA_10, cat, catB3, aadB, aph(3')-III, AAC(3)-Ib, bacA_1, blaPer-1, blaIMP, blaTEM, blaKPC, blaDHA, cblA, ermC, ermY, ermX, mdtL, cusF, copD, qacA, mecA, dfrF, arnA, sul1, sulA, vat(A), IS6100, ISS1N, Intl1, blaCTX-M, blaIMP, mefA_10, tolC, mdfF, acrA, dfrA27, aac(6')-IIa, vanA, intl3, and TTV. These genes were associated with resistance to various antibiotics such as fluoroquinolones, macrolides, chloramphenicol, aminoglycosides, beta-lactams, polymyxins, sulfonamides, and others. The study also found that the resistome composition varied between upstream and downstream sites, indicating the impact of WWTP effluents on the distribution of ARGs in river biofilms.