Antimicrobial resistance in marine mammals

Recent studies have shown that antibiotics are not the sole cause of AMR; pollutants such as heavy metals (HMs) and biocides create selective pressures within microbial communities leading to the development of resistant genes within the community (Singer 2017). Once in a body of water, pollutants cause long-term persistent effects. They are transported by mass flow within the atmosphere and water causing long-range effects, pollution resulting from anthropogenic activity has been identified in remote environments such as Antarctica (Giudice et al. 2012; Singer 2017).
Sediments are the natural collectors of pollutants, AMR genes are often passed to higher trophic levels via bacteria within sediments. Bacteria possess the biochemical and genetic ability to remediate pollutants such as HMs and biocides, leading to direct or indirect selection of AMR genes (Lo Giudice et al. 2012).
There will be three main areas of analytical research to identify which pollutants are present within the ecosystems of seals and microbial communities, which are outlined below:
Seal samples will be obtained from various institutes; there is no intention to sacrifice seals for the purpose of the study. The species of seal will be selected depending on their availability. The study will require a seal source from an area with little anthropogenic activity (the control) and a sample from an area with high anthropogenic activity (the variable) (Troisi et al. 2020).
Throughout the project multiple components of the seal will be analysed, for example: blood plasma, tissues, organs, hair and faeces. Various analytical techniques will be used throughout analysis such as: HPLC, GC-MC, ICP-OES, ICP-AES and FTIR (Troisi et al. 2020; Liang G et al. 2017), with analytic techniques being applied on a case-by-case basis dependant on the component being analysed. Organisms that have been identified as a key part of the seals diet will also be analysed to again a greater understanding about how AMR genes are passed to higher trophic levels.
As sediments are a key stockpile of pollution, samples will be collected from the same bodies of waters that the seal samples were obtained. If this is not possible, areas will be selected within the UK with similar levels of anthropogenic activity. The sediments will be prepared using the same
method as Yi, Y et al. and analysed using techniques such as ICP-MS, ICP-AES and AFS (Yi et al. 2011). XRF and XRD could be used in tandem to analyse the bulk chemistry of the sediments. Finally, water samples will be collected from the same body of water as the sediments and analysed using methods including ICP-OES and AAS.
In addition to the analytical research, the project will work alongside conservation centres to study and treat seals suffering from the consequences of pollution and AMR, with the aim of them being released back into the wild after treatment.