Antibiotics in wastewater: Exploring the sources, links to antibiotic resistance, and strategies for their removal

Antibiotics in wastewater have posed significant health concern as they promote the development and spread of antibiotic-resistance genes (ARGs) among bacterial populations. Several studies have reported the occurrence and diversity of antibiotics and their relation with ARGs in bacterial populations of wastewater samples collected from different wastewater treatment plants. Bacterial populations in wastewater are usually dominated by Acinetobacter, Pseudomonas, and Escherichia, which contain ARGs. Wastewater derived from hospitals, pharmaceutical industries, animal farms, and domestic sources harbors a diverse range of ARGs, including those conferring resistance to β-lactam, macrolides, sulfonamides, and fluoroquinolones. The abundance of ARGs significantly correlates with the concentrations of antibiotics in the wastewater. Bacterial strains typically employ efflux pumps, target-site modulation, and enzymatic degradation of antibiotics to impart resistance. Horizontal gene transfer plays a significant role in the propagation of antibiotic resistance among bacterial strains. Several sustainable approaches, such as membrane filtration, adsorption, photocatalysis, and the Advanced Oxidation Process, offer promising advantages for better management of pharmaceutical wastes. Therefore, the present study highlights the occurrence and abundance of antibiotics and ARGs in wastewater and the need for sustainable approaches to mitigate antibiotic resistance.