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Fungi in water pose great risk to immune-compromised individuals

24 July 2023 | Story André Damons | Photo Supplied

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

Bloemfontein's quality of tap water compares very favourably with bottled water

2009-08-04

The quality of the drinking water of five suburbs in Bloemfontein is at least as good as or better than bottled water. This is the result of a standard and chemical bacterial analysis done by the University of the Free State’s (UFS) Centre for Environmental Management in collaboration with the Institute for Groundwater Studies (IGS).

Five samples were taken from tap water sources in the suburbs of Universitas, Brandwag, Bain’s Vlei, Langenhoven Park and Bayswater and 15 samples were taken of different brands of still and unflavoured bottled water. The samples were analysed at the laboratory of the IGS, while the interpretation of the analysis was done by the Centre for Environmental Management.

“We wanted to evaluate the difference in quality for human consumption between tap water and that of the different brands of bottled water,” said Prof. Maitland Seaman, Head of the Centre for Environmental Management.

“With the exception of two samples produced by multinational companies at their plants in South Africa, the different brands of bottled water used for the study were produced by South African companies, including a local small-scale Bloemfontein producer,” said Prof. Seaman.

According to the labels, the sources of the water vary from pure spring water, to partial reverse osmosis (as an aid to standardise salt, i.e. mineral, content), to only reverse osmosis (to remove salts). (Reverse osmosis is a process in which water is forced under pressure through a pipe with minute pores through which water passes but no – or very low concentrations of – salts pass.)

According to Prof. Seaman, the analysis revealed some interesting findings, such as:

• It is generally accepted that drinking water should have an acceptable level of salt content, as the body needs salts. Most mineral contents were relatively higher in the tap water samples than the bottled water samples and were very much within the acceptable range of drinkable water quality. One of the bottled samples, however, had a very low mineral content, as the water was produced by reverse osmosis, as stated on the bottle. While reverse osmosis is used by various producers, most producers use it as an aid, not as a single method to remove nearly all the salts. Drinking only such water over a prolonged period may probably have a negative effect on the human physiology.

• The pH values of the tap water samples (8,12–8,40) were found to be slightly higher (slightly alkaline), like in all south-eastern Free State rivers (from where the water is sourced) than the pH of most of the bottled water samples, most of which are sourced and/or treated in other areas. Two brands of bottled water were found to have relatively low pH levels (both 4,5, i.e. acidic) as indicated on their bottles and as confirmed by the IGS analysis. The health implication of this range of pH is not significant.

• The analysis showed differences in the mineral content given on the labels of most of the water bottles compared to that found by IGS analysis. The possibility of seasonal fluctuation in content, depending on various factors, is expected and most of the bottling companies also indicate this on their labels. What was a rather interesting finding was that two pairs of bottled water brands claimed exactly the same mineral content but appeared under different brand names and were also priced differently. In each case, one of the pair was a well-known house brand, and the other obviously the original producer. In one of these paired cases, the house brand stated that the water was spring water, while the other (identical) “original” brand stated that it was spring water treated by reverse osmosis and oxygen-enriched.

• Nitrate (NO3) levels were uniformly low except in one bottled sample, suggesting a low (non-threatening) level of organic pollution in the source water. Otherwise, none of the water showed any sign of pollution.

• The bacterial analysis confirmed the absence of any traces of coliforms or E.coli in any of the samples, as was also indicated by the bottling companies. This is very reassuring. What is not known is how all these waters were sterilised, which could be anything from irradiation to chlorine or ozone treatment.

• The price of the different brands of bottled water, each containing 500 ml of still water, ranged between R3,99 and R8,99, with R5,03 being the average price. A comparison between the least expensive and the most expensive bottles of water indicated no significant difference in quality. In fact, discrepancies were observed in the most expensive bottle in that the amount of Calcium (Ca) claimed to be present in it was found to be significantly different from what the analysis indicated (29,6 mg/l versus 0,92 mg/l). The alkalinity (CaCO3 mg/l) indicated on the bottle was also found to differ considerably (83 mg/l versus 9,4 mg/l). The concentration of Total Dissolved Salts (TDS) was not given on the product.

“The preference for bottled water as compared to Bloemfontein’s tap water from a qualitative perspective as well as the price discrepancy is unjustifiable. The environmental footprint of bottled water is also large. Sourcing, treating, bottling, packaging and transporting, to mention but a few of the steps involved in the processing of bottled water, entail a huge carbon footprint, as well as a large water footprint, because it also requires water for treating and rinsing to process bottled water,” said Prof. Seaman.

Media Release
Lacea Loader
Deputy Director: Media Liaison
Tel: 051 401 2584
Cell: 083 645 2454
E-mail: loaderl.stg@ufs.ac.za
3 August 2009

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