Environmental Dissemination of Antibiotic Resistance in Water Sources and Its Impact on Public Health

The rise and spread of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in water environments is a major global issue in public health today. The current study examined the occurrence of ARB and the diversity of clinically significant ARGs in six different types of water sources in an urban-peri-urban environment. We collected 1,800 water samples over a one-year period from municipal drinking water, surface water from rivers and lakes, hospital waste water, wastewater treatment plant (WWTP) influent and effluent, and agricultural runoff. Selective and differential media were used for isolation and phenotypic identification of ARB. Antibiotic resistance was tested using the Kirby-Bauer disk diffusion method for 17 antibiotics from seven different classes. One-way ANOVA, Tukey's post-hoc test and Spearman's correlation were used to compare data (α = 0.05). The greatest abundance of ARB was observed in hospital wastewater (71.3%) and WWTP influent (64.5%) with statistically significant decreases post-treatment (WWTP effluent: 43.2%; p < 0.001). But effluent concentrations were significantly higher than drinking water (p < 0.001). The intI1 integrase gene, which is a good indicator of human contamination and horizontal gene transfer, was found to be most abundant in all wastewater-impacted environments. Multidrug resistance (MDR) was found in 62% of hospital wastewater and 41% of agricultural runoff isolates. Traditional wastewater treatment systems fail to remove ARB and ARGs from the effluents, impacting surface water systems.