Drinking water sources as hotspots of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs): Occurrence, spread, and mitigation strategies

The widespread use of antibiotics has rapidly increased the prevalence of antibiotic-resistant bacteria (ARB) and their associated antibiotics resistance genes (ARGs), posing a tremendous environmental challenge and high health risks to the global population. Drinking water sources (DWSs) represent critical hotspots for ARGs and ARB creation and spread, threatening ecological safety with severe consequences to human and animal health. DWSs can contain a variety of ARGs and pathogens if contaminated by manure-contaminated soil, antibiotic-containing wastewater, and urban and hospital sewage. Hundreds of ARGs against a wide range of antibiotics have been detected in microorganisms in several DWSs. Wastewater treatment plant (WWTP) effluents containing untreated antibiotics and their related ARB and ARGs are directly discharged into lakes, rivers, and groundwater sources used as DWSs. The generation and accumulation of biofilms in DWSs is one factor that accelerates ARB and ARG dissemination through horizontal gene transfer (HGT). This review critically summarizes recent studies on the origin and occurrence of ARB and ARGs in DWSs. Factors facilitating ARB and ARG dissemination and development have also been analyzed; in addition, mechanisms and processes that control the dissemination and spread of ARB and ARGs in DWSs were elucidated, along with the impact of biofilms on ARG abundance, proliferation, and spread in DWSs.