In this opinion piece, NSSN Ambassador at UNSW Professor Ewa Goldys, discusses the implications of the latest research on mycobacteria in our drinking water and the need for related sensing technologies.

Allergies are as widespred as they are mysterious. From sneezing to life threatening reaction to peanuts, from rheumatoid arthritis, to Crohn disease, millions of people are affected. They are also rapidly growing with 70% increase of allergy cases expected by 2050 (over 7 million Australians). Nobody knows why.

We expect that something really common could be to blame. There is no clear answer so far. But, as science advances, we are starting to see new connections pointing to contamination inadvertently present even in highly purified tap water.

Despite treatments such as chlorination used worldwide, our tap water contains abundant quantities (~1-50 organisms/ml) of generally non-pathogenic bacteria called mycobacteria and their residues.

Neither the general population nor water authorities are yet concerned with these mycobacteria, because they appear to be mostly harmless to healthy humans. So why should we be worried?

Mycobacteria are now recognised to have broad effects on immunity. For example, mycobacteria indirectly affect respiratory health, with depressed immunity facilitating viral infections. Strong links have also been reported to a reduced efficacy of vaccinations pointing to the possibility of immune regulation by mycobacteria, particularly the most common type called Mycobacterium avium subsp. Paratuberculosis (MAP).

Researchers now think that MAP proteins and some human proteins are similar. Upon exposure to MAP, the immue system learns to recognise and destroy these microorgnisms – but then it mistakenly attempts to destroy these similar proteins – thus attacking the body it is meant to protect.

This collateral damage may then result in autoimmune conditions. Thus, mycobacteria and also, importantly, the biomolecules they carry on their surface (e.g. muramyl dipeptide) may represent a trigger of abnormal host immune response. Such disturbed autoimmunity in common language means allergies.

Humans have now deeply altered the mycobacteria distribution. The key reason is industrial food production. Production animals grown for food such as cows and pigs, spend their lives in massive industrial “factory farms,” where animals are squeezed into limited spaces by the thousands. In such environments animal disease caused by MAP can be rampant. Massive amounts of mycobacteria resulting from this epidemics then pile up in the soil and from there, they accumulate in our waterways where they can remain viable for years. Renowned for their toughness and ability to live through harsh conditions, the mycobacteria are able to survive water treatments (e.g. chlorination) and take residence in biofilms of our ageing water infrastructure.

Further research into the immune effects of mycobycteria in our waterways will cast a new light on where and when the public may be most at risk of exposure. The quantification of this response will help determine the extent of threat and generate quantitative data informing prospective health safety standards for mycobacteria (e.g. MAP) that currently do not exist.

In order to be able to implement such standards, we need innovative sensing techniques to monitor key relevant mycobacteria species, their immunogenic products in the water supply. New sensors will allow us to achieve an unparalleled level of insight into mycobacterial ecology in situ, in real time, and its immunological effects.

As a health-conscious nation, it is necessary that we understand how our immunological health is affected by waterborne mycobacteria and related contaminants. This key step will enable future public health interventions such as the introduction of new standards or community guidance.

The outcomes will help identify actions (such as modifying acceptable turbidity limits, or water purification of by reverse osmosis) with industry, to specifically reduce or remove harmful types of mycobacteria and their immunogenic products from urban water.

Australia is the allergy capital of the world. But, if the above research ideas are realised, we will be able to drink water from the tap without thinking what is this doing to our allergies. We can only say “cheers to that!”

Professor Ewa M. Goldys is Deputy Director of the Australian Research Council Centre of Excellence in Nanoscale Biophotonics (cnbp.org.au) and Professor at the Graduate School of Biomedical Engineering, the University of New South Wales, Sydney, Australia. She is Fellow of the Australian Academy of Technological Science and Engineering (ATSE), Society for Optics and Photonics (SPIE), the Optical Society and winner of the 2016 Australian Museum Eureka Prize for ‘Innovative Use of Technology’.

Her research spans the interface of ultrasensitive optical characterization, biotechnology, materials science and photonics. Her expertise in ultrasensitive optical characterisation and nanotechnology led to the development of novel approaches to biochemical and medical sensing and diagnostics. Current projects focus on label-free non-invasive high content cellular imaging and characterisation of cell subpopulations, on ultrasensitive chemical (CRISPR) sensors and theranostics.

Learn more about Ewa here.

Sensing the solution to cleaner and safer drinking water