Canada_IPAP: Amoebae with antimicrobial resistant endsymbionts (AWARE)

Antimicrobial resistance represents bacteria's ability to withstand harmful chemicals; most popularly, their ability to resist antibiotics has been most concerning. These traits allow disease-causing pathogens (for example) to survive antibiotic therapy. Less commonly known are the impacts of "other" compounds (e.g., disinfectants) and other organisms in nature that may worsen the problem.

In particular, quaternary ammonium compounds (QACs) are high-consumption chemicals used to make emulsifiers, fabric softeners, corrosion inhibitors and personal care products. They are also the most common active ingredients in sanitizing and disinfecting products; as such, they are a candidate for developing resistance. Therefore, we will examine their role in resistance development because of their extensive use in the food preparation industry.

More importantly, The project examines the role of free-living amoebae (a protozoan found in waters and sediment) as a mechanism and vector in developing and spreading antimicrobial-resistant bacteria. Free-living amoebae harbour bacteria and essentially could be protected, to an extent, from toxic compounds in the environment. However, for some additional reason, they further enhance the potential for bacteria to become resistant. Some of the bacteria are fish pathogens. So their mechanism as a driving force for drug resistance must be investigated.

This investigation will take place within a whole-lake exposure study at the Experimental Lakes Area (Ontario), which includes the impacts of multiple trophic levels within a lake--including Lake Trout. Comparisons of bacterial populations and their resistance traits in the water, sediment, amoebae and fish will be made as preliminary results towards understanding whether similarities in their distribution do occur and whether QAC disinfectants also contribute to the selection pressure.

This is a partnership development grant with a unique opportunity to collaborate with other researchers to better understand the biological mechanisms of antimicrobial resistance in a real-life context and their risks in the aquaculture and fishing industries.

Antimicrobial resistance (AMR) is a survival adaptation mechanism. AMR traits can emerge in microorganisms exposed to pollutants employed in interactions with other microbes from different biological kingdoms. In addition, the chemical and ecological community pressure increases the risk of the likelihood that AMR can transfer between microorganisms through mobile genetic elements. The biological mechanisms by which AMR develops under these circumstances are not yet fully understood. In this project, we aim to investigate the multi-trophic linkages of AMR in aquatic systems with the long-term goal of improving farmed-fish health and welfare. Likely, improving aquaculture health and welfare will also benefit wild fish stocks. We will work with the International Institute for Sustainable Development's flagship Experimental Lakes Area to develop a programme of work focused on understanding how microbial community interactions, composition, resistome, and mobile genetic elements contribute to the development of AMR. Specifically, herein we will generate preliminary data on the biological mechanisms triggered in cross-kingdom microbial communities that generate AMR. The project will result in a library of microbial isolates (amoebae and bacteria) for future work that includes dissecting the mechanisms by which bacteria are resistant to amoebic digestion, leading to their survival and, within amoebae, potentially establishing themselves as endosymbionts. The results will elucidate complex biochemical relationships that underpin microbial adaptation and evolution.