By Gofaone Motsamai

When water gushes from a rural borehole, many see purity, but beneath that clear stream could lie invisible fungal organisms capable of causing serious infections. To protect public health, South Africa should introduce inclusive microbial monitoring, according to a North-West University (NWU) study.

Conducted by Rebaone Mofokeng, Prof Carlos Bezuidenhout and Dr Deidré van Wyk from NWU’s Unit for Environmental Sciences and Management, the study argues that South Africa’s water safety regulations should be expanded beyond bacteria to include fungal pathogens, especially yeasts, found in groundwater.

“Despite routine surveillance of bacterial indicators, fungal contaminants, particularly yeasts, have received little attention in South Africa,” says Mofokeng. “This gap creates a blind spot in water safety, especially in communities that rely on untreated groundwater for daily use.”

Groundwater is the main source of drinking water for millions in rural and semi-arid parts of South Africa. While generally considered safe, the research notes that anthropogenic activities such as agriculture, waste disposal and climate change are increasingly contaminating these sources.

Health impacts of yeasts range from mild to life threatening

The study highlights that traditional monitoring systems mainly focus on bacterial indicators such as E coli, neglecting fungal pathogens like candida, cryptococcus and rhodotorula species. These yeasts can cause mild skin infections or life-threatening diseases in immunocompromised individuals.

“Yeasts are increasingly recognised as complementary indicators that capture contamination routes overlooked by bacterial monitoring alone,” Mofokeng explains. “By incorporating yeast detection into water quality frameworks, we can achieve a more holistic assessment of groundwater safety.”

Climate change implicated

The paper, published in Total Environment Microbiology, also links the persistence of pathogenic yeasts in groundwater to changing environmental conditions. Climate change, agricultural runoff and rising temperatures are said to promote the survival of thermotolerant fungi capable of adapting to both environmental and human hosts.

“Global warming may promote the proliferation of thermotolerant pathogens such as candidozyma auris and cryptococcus neoformans,” says Mofokeng. “These species

have already been identified as critical health threats by the World Health Organisation.”

South Africa’s current water quality guidelines regulate bacterial and parasitic indicators but exclude fungi. The researchers argue that this omission leaves communities vulnerable to emerging fungal pathogens.

Gaining a clearer picture

To address the gap, the study recommends integrating advanced molecular technologies such as next-generation sequencing and Oxford Nanopore platforms into groundwater testing. These tools, according to the authors of the article, can detect both culturable and non-culturable microorganisms, providing a clearer picture of microbial diversity in water.

“Traditional culture-based techniques cannot capture the full range of yeast diversity,” says Mofokeng. “Using high-throughput molecular tools allows us to detect pathogenic yeasts that would otherwise go unnoticed.”

The study concludes with a call for policy reform and collaboration between microbiologists, hydrologists and policymakers to safeguard South Africa’s water resources. Mofokeng emphasises that revising the country’s water safety standards would align with Sustainable Development Goal 6, which seeks universal access to safe and clean water.

“Recognising fungi, especially yeast, as important water pathogens is a step toward inclusive microbial monitoring,” she adds. “Safe water is not just about bacteria; it’s about everything we can’t see but must account for.” Link to the full article: https://doi.org/10.1016/j.temicr.2025.100038

Rebaone Mofokeng

Prof Carlos Bezuidenhout

Dr Deidré van Wyk