Environmental hazards from pollution of antibiotics and resistance-driving chemicals in an urban river network from Malawi.

African communities have a high prevalence of antimicrobial-resistant bacterial carriage, alongside high levels of antibiotic usage and environmental pollution. Limited access to water, sanitation and hygiene infrastructure and wastewater treatment facilities enables the dissemination of resistant bacteria, antimicrobials and antibiotic resistance-driving chemicals (ARDCs) into local rivers. Few data exist quantifying the chemical drivers of antimicrobial resistance (AMR) in urban aquatic environments from African settings. In this longitudinal surveillance study, we investigated an urban river network in Blantyre, Malawi over a continuous 12-month period, identifying a broad-range of chemical pollutants, including antibiotics, common pharmaceuticals, agricultural and industrial chemicals and heavy metals. Antimicrobial concentrations were found at levels selective for AMR and ARDCs exhibited seasonal variations, indicating that deficient sanitation infrastructure and anthropogenic factors result in high antibiotic and ARDC levels entering the river systems, which serve as an important ecological niche for the acquisition, maintenance and transmission of AMR.