Antimicrobial resistance in Antarctica: is it still a pristine environment?

Abstract

Although the rapid spread of antimicrobial resistance (AMR), particularly in relation to clinical settings, is causing concern in many regions of the globe, remote, extreme environments, such as Antarctica, are thought to be relatively free from the negative impact of human activities. In fact, Antarctica is often perceived as the last pristine continent on Earth. Such remote regions, which are assumed to have very low levels of AMR due to limited human activity, represent potential model environments to understand the mechanisms and interactions underpinning the early stages of evolution, de novo development, acquisition and transmission of AMR. Antarctica, with its defined zones of human colonisation (centred around scientific research stations) and large populations of migratory birds and animals, also has great potential with regard to mapping and understanding the spread of early-stage zoonotic interactions. However, to date, studies of AMR in Antarctica are limited. Here, we survey the current literature focussing on the following: i) Dissection of human-introduced AMR versus naturally occurring AMR, based on the premise that multiple drug resistance and resistance to synthetic antibiotics not yet found in nature are the results of human contamination ii) The potential role of endemic wildlife in AMR spread There is clear evidence for greater concentrations of AMR around research stations, and although data show reverse zoonosis of the characteristic human gut bacteria to endemic wildlife, AMR within birds and seals appears to be very low, albeit on limited samplings. Furthermore, areas where there is little, to no, human activity still appear to be free from anthropogenically introduced AMR. However, a comprehensive assessment of AMR levels in Antarctica is virtually impossible on current data due to the wide variation in reporting standards and methodologies used and poor geographical coverage. Thus, future studies should engage directly with policymakers to promote the implementation of continent-wide AMR reporting standards. The development of such standards alongside a centralised reporting system would provide baseline data to feedback directly into wastewater treatment policies for the Antarctic Treaty Area to help preserve this relatively pristine environment. Video Abstract.

Keywords: Aminoglycosides; Anthropogenic; Efflux pumps; Horizontal gene transfer; Metagenomics; Sewage; Wastewater treatment; β-Lactam.

Fig. 1

Top panel: map of Antarctica showing the locations in which all the studies analysed in this review took place. If a single author investigated more than one site and clearly distinguished the results of each site, each sample site was recorded individually in Additional file 3. Markers in the sea are from cruise samplings. Bottom left panel: summary of studies conducted in the South Shetland Islands according to the types of antibiotic identified at each site; full details of studies are detailed in Additional file 4. Bottom right panel: summary of resistance found to β-lactams and aminoglycosides in Antarctica; full details of studies are detailed in Additional file 5. NB: when an antibiotic class is annotated as not being present, e.g. resistance to β-lactams not aminoglycosides, this means that the relevant study did not find resistance to aminoglycosides, rather than it being absent