Antibiotic residues in the environment of South East Asia

• Antibiotic manufacture, as well as its use, contributes to antibiotic residues in the environment, which leads to development of resistant bacteria • In South East Asia, wastewater containing antibiotics is often directly released into the environment without sufficient treatment • Research must focus on developing efficient, affordable, small scale treatment plants to eliminate antibiotic residues and resistant bacteria at the point of origin, and tools to monitor their levels in the environment T he global action plan on antimicrobial resistanceemphasises the One Health approach—seeing humans, animals, the food chain, the environment, and the interconnectedness between them as one entity. With growing economic development in South East Asia, the production and use of antibiotics—and therefore also their residues in the environment—are expected to increase. Antibiotic residues in the environment lead to resistant bacteria through selective pressure. Theoretically, a chance interaction between a single molecule of an antibiotic and a bacterium can trigger natural selection for resistance, or a mutation favouring resistance. Subsequently, a vertical gene transfer (from one generation to another) or a horizontal gene transfer (transfer of resistance genes from one bacterium to another through a plasmid) may occur (fig 1). Identification of a complete identical sequence of antibiotic resistance genes from soil bacteria and clinical pathogens has demonstrated the potential for horizontal gene transfer between environmental antibiotic resistant bacteria and pathogenic bacteria. Humans may be exposed to antibiotic residues or directly to antibiotic resistant bacteria, including pathogens, through food or environment, and potentially be infected. Reduced effectiveness of antibiotics may result in prolonged or poorly controlled infections. In this paper, we identify pathways that contribute to antibiotic residues in the environment and propose priority actions for South East Asian countries to monitor and limit this.