Multi-site sampling and risk prioritization of antibiotic resistance genes in sewage environments

Abstract

The spread of antibiotic resistance across human and environmental habitats is a global public health challenge. In this study, we investigate the public health relevance of antibiotic resistance found in wastewater by combining metagenomic sequencing of wastewater environments with risk prioritization of resistance genes. We find that many of the genes commonly found in wastewater are not readily present in humans. Ranking antibiotic resistance genes based on their potential pathogenicity and mobility reveals that most of the antibiotic resistance genes in wastewater are not directly clinically relevant. Residential sewage was found to be of greater risk to human health than wastewater treatment plants and can be as risky as hospital effluent. Across countries, we show that differences in antibiotic resistance can, in some cases, resemble differences in antibiotic drug consumption. Finally, we find that the flow of antibiotic resistance genes is influenced by geographical distance and environmental selection.