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24 July 2023 | Story André Damons | Photo Supplied
Tyla Baker
Tyla Baker, a postgraduate student in the Department of Microbiology and Biochemistry at the University of the Free State (UFS).

Yeast and other filamentous fungi, which pose a great risk to the health of immune-compromised or suppressed individuals, can be found in various drinking water sources such as ground, spring, surface, and tap water. These opportunistic pathogens may cause severe to fatal infections and can range from superficial to bloodstream or systemic infections.

This is according to Tyla Baker, a postgraduate student in the Department of Microbiology and Biochemistry at the University of the Free State (UFS). She is studying for her MSc degree in Microbiology under the supervision Prof Carlien Pohl-Albertyn, National Research Forum (NRF) SARChI Research Chair in Pathogenic Yeasts. Prof Jacobus Albertyn and Dr Jolly Musoke are her co-supervisors.

Baker says the fungi in the water highlights that current water treatment processes are not efficient in their removal from water destined for household use. “These infections may not be harmful to people with healthy immune systems, but do pose a great risk to the health of immune-compromised or suppressed individuals. 

Definite possibility to contract fungal infections from polluted water 

“As the number of people with immune systems that are less functional (e.g. premature babies, elderly persons, people with cancer, diabetes or other serious diseases, HIV+ persons, transplant patients) increases, the number of people at risk of fungal infection also increases,” says Baker.

According to Baker, a previous study done in Brazil has identified yeast in bottled mineral water as well as municipally supplied tap water. The potential risk to contract fungal infections from polluted water sources is a definite possibility but more research is required to fully understand and determine the level of risk and the extent of its effects, she says. In the context of Mangaung, it is a concern that untreated water from sewage works as well as other sewage often leaks into the environment (as evidenced by numerous recent articles in local newspapers). These waters are potential carriers of large numbers of pathogens (including pathogenic yeasts/fungi) that may increase the risk to people coming into contact with it.

Baker says there is a good chance people are consuming these kinds of micro-organisms daily, considering that yeast and other filamentous fungi can also form biofilms inside pipes and spread as the impact of water flow dislodges these cells. “People will not even be aware that they are consuming these micro-organisms, some fungi are considered nuisance microbes and may cause a change in the smell and taste of water which may act as an indicator that the water is contaminated, but tests would be needed to confirm this,” she says.

The effects of consuming these fungi are still a grey area of research since the full extent of the consumption of yeast is still unknown, but there are studies being conducted to elucidate the full impact of this occurrence, says Baker. The risk depends on the immune status of the person, the specific species of yeast/fungus ingested, and the number of cells/spores ingested.

Culture-dependent and independent methods

 “It is important to know that many pathogenic yeasts and other fungi are opportunistic pathogens, meaning they infect individuals whose immune systems are compromised due to various reasons such as illness (HIV/AIDS, cancer, TB etc.), undergoing organ transplants or even something as simple as using antimicrobial agents such as antibiotics. 

“Taking this into account, along with the HIV/AIDS statistics in South Africa, which has a prevalence rate of 13,7% with approximately 8,2 million people in 2021 living with HIV, these individuals are more susceptible to infection by these opportunistic pathogens. Some of these pathogenic yeasts are also multidrug resistant or show resistance to readily available antifungals, such as fluconazole, which hinders the ability of healthcare professionals to efficiently treat infections to avoid fatal/severe outcomes,” explains Baker.  

For her studies, she will be testing for fungi in water by using a combination of culture-dependent and independent methods to try and identify yeast present in wastewater. Baker says culture-dependent techniques will include culturing (growing) yeast on an appropriate medium while culture-independent techniques will include more intricate molecular work in the form of a multiplex PCR (polymerase chain reaction) which will enable her to identify an array of pathogenic yeasts present in samples.

According to Baker, people can stay safe by boiling water before drinking it, although temperatures above 100°C are required to kill most harmful microbes. Regular cleaning of shower heads and faucets help to prevent build-up which may act as a surface to which fungi will attach to and grow. Another way to stay safe is to maintain and regularly inspect water filters for damage and avoid contact with untreated sewage.

News Archive

Mushrooms, from gourmet food for humans to fodder for animals
2016-12-19

Description: Mushroom research photo 2 Tags: Mushroom research photo 2 

From the UFS Department of Microbial Biochemical and
Food Biotechnology are, from left: Prof Bennie Viljoen,
researcher,
MSc student Christie van der Berg,
and PhD student Christopher Rothman
Photo: Anja Aucamp

Mushrooms have so many medicinal applications that humans have a substance in hand to promote long healthy lives. And it is not only humans who benefit from these macrofungi growing mostly in dark spaces.

“The substrate applied for growing the mushrooms can be used as animal fodder. Keeping all the medicinal values intact, these are transferred to feed goats as a supplement to their daily diet,” said Prof Bennie Viljoen, researcher in the Department of Microbial, Biochemical and Food Biotechnology at the UFS.

Curiosity and a humble start
“The entire mushroom project started two years ago as a sideline of curiosity to grow edible gourmet mushrooms for my own consumption. I was also intrigued by a friend who ate these mushrooms in their dried form to support his immune system, claiming he never gets sick. The sideline quickly changed when we discovered the interesting world of mushrooms and postgraduate students became involved.

“Since these humble beginnings we have rapidly expanded with the financial help of the Technology Transfer Office to a small enterprise with zero waste,” said Prof Viljoen. The research group also has many collaborators in the industry with full support from a nutraceutical company, an animal feed company and a mushroom growers’ association.

Prof Viljoen and his team’s mushroom research has various aspects.

Growing the tastiest edible mushrooms possible
“We are growing gourmet mushrooms on agricultural waste under controlled environmental conditions to achieve the tastiest edible mushrooms possible. This group of mushrooms is comprised of the King, Pink, Golden, Grey, Blue and Brown Oysters. Other than the research results we have obtained, this part is mainly governed by the postgraduate students running it as a business with the intention to share in the profit from excess mushrooms because they lack research bursaries. The mushrooms are sold to restaurants and food markets at weekends,” said Prof Viljoen.

Description: Mushroom research photo 1 Tags: Mushroom research photo 1 

Photo: Anja Aucamp

Natural alternative for the treatment of various ailments
“The second entity of research encompasses the growth and application of medicinal mushrooms. Throughout history, mushrooms have been used as a natural alternative for the treatment of various ailments. Nowadays, macrofungi are known to be a source of bioactive compounds of medicinal value. These include prevention or alleviation of heart disease, inhibition of platelet aggregation, reduction of blood glucose levels, reduction of blood cholesterol and the prevention or alleviation of infections caused by bacterial, viral, fungal and parasitic pathogens. All of these properties can be enjoyed by capsulation of liquid concentrates or dried powdered mushrooms, as we recently confirmed by trial efforts which are defined as mushroom nutriceuticals,” he said.

Their research focuses on six different medicinal genera, each with specific medicinal attributes:
1.    Maitake: the most dominant property exhibited by this specific mushroom is the reduction of blood pressure as well as cholesterol. Other medicinal properties include anticancer, antidiabetic and immunomodulating while it may also improve the health of HIV patients.
2.    The Turkey Tail mushroom is known for its activity against various tumours and viruses as well as its antioxidant properties.
3.    Shiitake mushrooms have antioxidant properties and are capable of lowering blood serum cholesterol (BSC). The mushroom produces a water-soluble polysaccharide, lentinan, considered to be responsible for anticancer, antimicrobial and antitumour properties.
4.    The Grey Oyster mushroom has medicinal properties such as anticholesterol, antidiabetic, antimicrobial, antioxidant, antitumour and immunomodulatory properties.
5.    Recently there has been an increased interest in the Lion’s Mane mushroom which contains nerve growth factors (NGF) and may be applied as a possible treatment of Alzheimer’s disease as this compound seems to have the ability to re-grow and rebuild myelin by stimulating neurons.
6.    Reishi mushrooms are considered to be the mushrooms with the most medicinal properties due to their enhancing health effects such as treatment of cancer, as well as increasing longevity, resistance and recovery from diseases.


Description: Mushroom research photo 3 Tags: Mushroom research photo 3


Valuable entity for the agricultural sector
Another research focus is the bio-mushroom application phenome, to break down trees growing as encroaching plants. This research is potentially very valuable for the agricultural sector in the areas where Acacia is an encroaching problem. With this process, waste products are upgraded to a usable state. “It is therefore, possible to convert woody biomass with a low digestibility and limited availability of nutrients into high-quality animal fodder. By carefully selecting the right combination of fungus species to ferment agro-wastes, a whole host of advantages could become inherently part of the substrate. Mushrooms could become a biotechnological tool used to ‘inject’ the substrate that will be fed to animals with nutrition and/or medicine as the need and situation dictates,” said Prof Viljoen.

 

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