‘Disperse abroad in the land’: the role of wildlife in the dissemination of antimicrobial resistance

Abstract

Antimicrobial resistance (AMR) has been detected in the microbiota of many wildlife species, including long-distance migrants. Inadequately treated wastes from humans and livestock dosed with antimicrobial drugs are often assumed to be the main sources of AMR to wildlife. While wildlife populations closely associated with human populations are more likely to harbour clinically important AMR related to that found in local humans and livestock, AMR is still common in remote wildlife populations with little direct human influence. Most reports of AMR in wildlife are survey based and/or small scale, so researchers can only speculate on possible sources and sinks of AMR or the impact of wildlife AMR on clinical resistance. This lack of quantitative data on the flow of AMR genes and AMR bacteria across the natural environment could reflect the numerous AMR sources and amplifiers in the populated world. Ecosystems with relatively simple and well-characterized potential inputs of AMR can provide tractable, but realistic, systems for studying AMR in the natural environment. New tools, such as animal tracking technologies and high-throughput sequencing of resistance genes and mobilomes, should be integrated with existing methodologies to understand how wildlife maintains and disperses AMR.

Complexities in understanding antimicrobial resistance across domesticated animal, human, and environmental systems

“…Although not central to this review, brief mention of wildlife‐mediated AMR is needed because it highlights another difficult‐to‐detect but potentially important factor related to AMR dissemination in animal–human–environmental systems. Direct contact between humans and wildlife is typically not as intimate as with livestock or domestic animals; but wildlife, especially birds, has been shown to act as a vector for AMR transmission across the environment . For example, growing data suggest that ARB and ARGs may be dispersed by wild birds after exposure to sewage near rivers, spreading of sewage sludge onto farmland, and via direct exposure to the feces from livestock and companion animals .…”

Antimicrobial resistant and extended‐spectrum β‐lactamase producing Escherichia coli in common wild bird species in Switzerland

“…The emergence of AMR in wild birds is thought to be due to the dissemination of resistant bacteria or AMR genes from anthropogenic‐influenced habitats to the natural environment via contaminated water or feed (Guenther et al., ). In turn, wild birds may represent a reservoir for bacteria harboring clinically important resistance determinants (Arnold, Williams, & Bennett, ). Migratory wild birds in particular, are known to be disseminators of AMR into geographically distant ecosystems (Agnew, Wang, Fanning, Bearhop, & McMahon, ).…”

Satellite tracking of gulls and genomic characterization of faecal bacteria reveals environmentally mediated acquisition and dispersal of antimicrobial‐resistant Escherichia coli on the Kenai Peninsula, Alaska

“…Molecular epidemiological approaches, and data to support them, are needed to improve our understanding of the evolutionary processes that drive AMR and patterns of dissemination among landscapes and hosts (Baker, Thomson, Weill, & Holt, ). The integration of new technologies, such as next generation sequencing and animal tracking devices, may be particularly well suited to detail the maintenance and dispersal potential of AMR by wildlife (Arnold et al, ).…”

“…Bacteria exhibiting AMR was detected in wildlife at least three decades ago (Rolland, Hausfater, Marshall, & Levy, 1985), yet AMR surveillance in wildlife and environmental sources has received comparatively less attention than in human clinical environments and domestic livestock (Perez & Villegas, 2015). The source of AMR bacteria is often unknown (Pires, Duarte, & Hald, 2017), and therefore sampling of AMR in environmental sources could provide a reference for the distribution and prevalence of AMR genes pertinent to human and animal health (Arnold, Williams, & Bennett, 2016;Forsberg et al, 2012). As such, investigation of AMR in environmental sources is a key pillar in the application of a One Health approach (Robinson et al, 2016) and can improve our understanding of where AMR is acquired, maintained, mobilized and dispersed.…”

“…The integration of new technologies, such as next generation sequencing and animal tracking devices, may be particularly well suited to detail the maintenance and dispersal potential of AMR by wildlife (Arnold et al, 2016).…”