4 Concluding Thoughts

This literature review has shown that NCA may be used as a remediation strategy for the removal of driving agents (clinical antimicrobials, metals, biocides) from water and the environment. However, in order for this to occur, the method must be tailored to the specific driving agent intending to be removed, rather than aiming for a ‘one solution fits all’ approach.

Through applying the SPR framework to AMR several relevant pathways have been identified as opportunities for NCA to be applied in preventing AMR from spreading within the water and environment. NCA could be potentially effective in remediating against the concentration of heavy metals driving AMR. NCA for AMR could easily be integrated into current projects within Mott MacDonald. This report has identified that interception of pathways between agricultural runoff and surface water bodies, or between aquaculture farms and downstream water bodies, would be the most effective use of NCA for preventing the catchment-wide occurrence and circulation of AMR genes. One of the best examples of where this may be applied is within drainage ditches (both road-side and field-side).

Until further research has been completed; it is not recommended to use a NCA as an action plan for removing clinical antimicrobials from the water and environment for risk of accentuating the issue and creating a reservoir of antimicrobial daughter products of unknown effect within the environment. This report has also concluded that is a significant lack of research regarding the occurrence of other clinically used antimicrobials such as antifungals or antivirals.

Due to time constraints on the project, several key questions remain unanswered, some of which include:

● What is the role of the daughter products from the biodegradation of clinical antimicrobials in driving AMR?

● How does the role of NCA change when considering the controls of HGT and colonial expansion of point mutations separately within different environmental reservoirs?

● How can we tailor the NCA to the specific resistance mechanism we are trying to prevent? For example, removing the competitive advantage that maintaining traits, such as efflux pumps provide?

● What is the impact of increased AMR on agriculturally important symbiotic relationships, such as legumes and nitrogen fixing bacteria, and what role could NCA have to play?

● What role does work completed by Mott MacDonald currently have in accentuating AMR and how could this be improved?

● Too much research focuses on AMR within bacteria, to what extent are we seeing AMR within other pathogens and do the same chemicals drive AMR in viruses, fungi etc?

Despite many unanswered questions, several key areas of Mott MacDonald have been identified in which increased awareness of AMR would be beneficial:

● Ecology and landscape architecture: What role does the natural environment play in AMR?

● Water resources and flooding: current natural flood management projects could be tailored to also address AMR, flooding is a key pathway for spreading AMR genes between water environments and soil/ecological reservoirs of micro-organisms. Drainage ditches are https://mottmac-my.sharepoint.com/personal/bryony_osbourn_mottmac_com/Documents/AMR/Natural one of the main pathways for driving agents of AMR to pass from the land, particularly agriculture, to the water environment. https://mottmac-my.sharepoint.com/personal/bryony_osbourn_mottmac_com/Documents/AMR/Natural

● Contaminated land: How can current remediation strategies for industrial pollutants be tailored to address AMR? What role do current remediation strategies play in spreading AMR and crating reservoirs of AMR within the environment?