Anthropogenic environmental drivers of antimicrobial resistance in wildlife

Abstract

The isolation of antimicrobial resistant bacteria (ARB) from wildlife living adjacent to humans has led to the suggestion that such antimicrobial resistance (AMR) is anthropogenically driven by exposure to antimicrobials and ARB. However, ARB have also been detected in wildlife living in areas without interaction with humans. Here, we investigated patterns of resistance in Escherichia coli isolated from 408 wild bird and mammal faecal samples. AMR and multi-drug resistance (MDR) prevalence in wildlife samples differed significantly between a Sewage Treatment Plant (STP; wastes of antibiotic-treated humans) and a Farm site (antibiotic-treated livestock wastes) and Central site (no sources of wastes containing anthropogenic AMR or antimicrobials), but patterns of resistance also varied significantly over time and between mammals and birds. Over 30% of AMR isolates were resistant to colistin, a last-resort antibiotic, but resistance was not due to the mcr-1 gene. ESBL and AmpC activity were common in isolates from mammals. Wildlife were, therefore, harbouring resistance of clinical relevance. AMR E. coli, including MDR, were found in diverse wildlife species, and the patterns and prevalence of resistance were not consistently associated with site and therefore different exposure risks. We conclude that AMR in commensal bacteria of wildlife is not driven simply by anthropogenic factors, and, in practical terms, this may limit the utility of wildlife as sentinels of spatial variation in the transmission of environmental AMR.

Antibiotic-resistant <i>Escherichia coli</i> isolated from urban rodents in Hanoi, Vietnam

“…Prevalence of ESBL-producing E. coli in urban rodents (4/59, 6.8%) was also lower than livestock (20%) and healthy persons (35.2%) in Vietnam [39]. Since the role of wildlife has been documented in spreading AMR bacteria, the urban rodents may play as the maintenance host or vector for ESBL-producing and colistin-resistant isolates [53,57].…”

Genomic data reveal international lineages of critical priority Escherichia coli harbouring wide resistome in Andean condors (Vultur gryphus Linnaeus, 1758)

“…To understand the rapid spread and evolution of antimicrobial resistance, it is necessary to have an ecological approach that integrates human, animal and environmental health (Hassell et al., 2019; Larsson et al., 2018; Swift et al., 2019). However, there are critical knowledge gaps in understanding the real scale of antibiotic resistance in the environment; indeed, the role of wildlife is often overlooked in the epidemiology of medically important antibiotic‐resistant bacteria (Dolejska & Literak, 2019; Larsson et al., 2018).…”

Could honey bees signal the spread of antimicrobial resistance in the environment?

“…This could be due to the different selection pressures hypothesized to exist in the various environmental sites; indeed, the highest quantities of antibiotics usually found in areas with strong anthropogenic pressure such as soil used for livestock (Kay et al 2004). Swift et al (2019) investigated the resistance patterns of E. coli isolated from wildlife living in environments with potentially different selection pressures for AMR and concluded that the evaluation of resistance pattern of commensal bacteria isolated from wildlife is not driven simply by anthropogenic factors. In our study, there were no significant differences among the resistances found in the environmental sites, and this could be due to the small number of samples and to the high variability of the species isolated, or to the presence of more complex than simple anthropogenic causes.…”