Chapter 12 - Ecological health risks of antibiotic resistance: A perspective on the evidence, challenges, and research needs

Abstract

Antibiotic-resistant bacteria (ARB) and antibiotic resistance genes and the associated mobile genetic elements (MGEs) occur widely in environmental systems including soils, non-marine aquatic systems, plants, biota such as wildlife as well as air-borne bioaerosols. Consensus exists that antibiotic resistance in environmental systems poses significant ecological and human health risks. Here, we examined the literature to understand the environmental and ecological health risks of antibiotic resistance in environmental systems excluding marine environments and their ecology. The specific objectives were: (1) to summarize the occurrence of antibiotic resistance in non-marine environmental systems, and resistance and exposure mechanisms using the source-pathway-receptor-impact pathway, (2) to review the evidence on the environmental and ecological health risks of antibiotic resistance, and (3) to propose future research directions and knowledge gaps. In summary, evidence on the potential environmental and health risks of antibiotic resistance is currently inferential. Despite the widespread occurrence of antibiotic resistance in environmental systems, empirical evidence based on quantitative microbial risk assessment (QMRA) of ecological health risks is scanty. Possible reasons accounting for the lack of evidence, including that emerging from QMRA, are discussed. A hierarchical or ecosystem cascade concept is proposed as a framework for understanding the environmental and ecological health risks of antibiotic resistance at various levels or hierarchies of biological organization. The opportunities presented by emerging tools such as big data analytics, genomics, in-silico computational tools, and systems or network analysis are discussed. All in all, the present perspective calls for urgent research to generate empirical evidence on the environmental and ecological health risks of antibiotic resistance in environmental systems. Such evidence is critical for decision and policymaking, including the implementation of the One-World-One-Health approach for mitigating the risks of antibiotic resistance.