URVASHI ROY, ROJINA KHATUN AND MALAVIKA BHATTACHARYA
Abstract
Antibiotic resistance (AR) has become a major threat to public health across the globe, which has been linked to clinical misuse of antibiotics. Recent data indicate that the generation of antibiotic resistance genes (ARGs) and bacteria (ARBs) in the environment is largely caused by pollution from leftover medications, particularly antibiotics discharged by hospitals, manufacturing facilities, farms, and through household waste disposal. Several case studies from terrestrial and aquatic systems, environmental monitoring reports, and molecular data are all included in this review. Data from developed and developing countries were compared to understand the sources, transmission pathways, and potential control measures of antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARG). Pharmaceutical manufacturing plants and hospital wastewater were identified as the main environmental sources of antibiotics. These sources have drug levels significantly higher than calculated no-effect levels, which increases the selective pressures for resistance. Antibiotic resistance genes and multidrug-resistant bacteria have been regularly found in effluents, topsoil, and agricultural ecosystems, with effects exacerbated by co-selection with heavy metals and biocides. The case studies have shown high contamination levels near the pharmaceutical production facilities in developing countries. Resistance genes like blaNDM and blaCTX-M are commonly detected near the drug production sites. Comparisons across regions also revealed that even advanced wastewater treatments cannot fully remove resistance genes, which highlights the scale of the challenge. The findings suggest that pharmaceutical pollutants play a significant role in the development of antibiotic resistance, although it remains largely underrecognized. To protect ecosystems and human health, new strategies like phytoremediation processes, green chemistry, and biological remediation remain to be developed and tested. This includes strict laws, open monitoring, ecoâfriendly treatment methods, and public awareness campaigns.