Grants and Contributions:

Grant or Award spanning more than one fiscal year. (2017-2018 to 2022-2023)

There is no direct control of premise plumbing water quality in Canada nor in many international jurisdictions, yet over 60% of drinking water outbreaks and 80% of hospitalization insurance claims in North America are thought to be associated with the growth of opportunistic, premise plumbing pathogens (OPPP). Current water quality monitoring based on traditional faecal indicator bacteria (such as E. coli or enterococci) provides no predictive capability for the presence of OPPP, nor do the presence of total heterotrophs. With the growth in the use of alternative water sources, there is also increased potential for exposures to OPPP via harvested rainwater/stormwater and recycled wastewaters for potable and non-potable uses to deal with water scarcity and more sustainable water practices. Hence, unlike the control of enteric, waterborne pathogens, there is currently no risk-based, quantitative guidance available for regulations nor systematic best management guidance for OPPP control.

The majority of documented disease outbreaks result from aerosolized OPPP, such as from shower heads, humidifiers, jacuzzis, and spray hoses (including those used in dentistry), although non-tuburculous mycobacteria (NTM) are probably as important via dermal contact of water that results in wound/skin infections. Importantly, current control strategies for one class of OPPP may actually cause an increase in another. For example, use of monochloramine to control L. pneumophila outbreaks within hospital plumbing systems, appear to select for various NTM. While key abiotic (temperature, flow conditions, pipe material, presence of pipe corrosion products, disinfectant type etc.) and biotic (present of biofilm, amoebal hosts etc.) factors are known to enhance the likelihood of OPPP, there is surprisingly little information on the ecological interactions that may provide insights into lasting control strategies for OPPP.

Therefore there are three key themes of research within this proposal:
1) Pipe biofilm community and functional gene responses to control options Analysis to describe bacterial and microeukaryotic (principally free-living protozoa) community members under bio-augmentation and other control strategies, and correlation with functional gene metagenomic analyses to describe virulence and antimicrobial resistance (AMR) genes.
2) Identification of active but non-culturable as well as culturable states of OPPPs This theme will start by exploring ribosomal RNA (rRNA) targeted qPCR to improve sensitivity and specificity in detecting viable and relevant OPPP versus DNA-gene targeted approaches.
3) Characterization of biofilm-to-water-to-aerosol partitioning coefficients via use of novel bathroom aerosolization chambers to aid exposure characterization and develop critical control targets for design and use of bathroom and related water fixtures.