On-the-spot water test for dangerous form of E.coli developed by Irish scientists

Technology predicted to help protect people drinking water from private sources including groundwater wells

Dr Louise O’Connor and Dr Zina Alfahl of the University of Galway testing water at Salthill, Galway, using a rapid test for STEC, the most dangerous form of E. coli found in water. Photograph: Martina Regan
Dr Louise O’Connor and Dr Zina Alfahl of the University of Galway testing water at Salthill, Galway, using a rapid test for STEC, the most dangerous form of E. coli found in water. Photograph: Martina Regan

A new portable technology for on-the-spot testing of drinking water quality to detect one of the most dangerous types of E.coli bacteria has been developed by University of Galway scientists.

Ireland regularly had the highest incidence rates of the pathogen shiga toxigenic escherichia coli – known as STEC – in Europe, while one in 20 small private water supplies and private group schemes failed to meet E.coli standards in 2023, the EPA reported last month.

STEC produces the harmful shiga toxin which if ingested by humans can cause severe stomach illnesses and in some cases life-threatening complications, especially in children under five, older people and immunocompromised individuals.

A team led by Dr Zina Alfahl and Dr Louise O’Connor developed the technology for rapid, sensitive and accurate testing of STEC in water sources. Their results were published on Wednesday in the journal Microbiology.

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“Our technology is a significant advancement in on-site water testing. It is portable, straightforward and safe to use. It is accurate, highly sensitive and the results are delivered quickly on-site,” Dr Alfahl said.

They hope environmental health officers and operators of groundwater schemes use the technology on-site allowing for more frequent testing “especially in or after extreme weather, periods of intense rainfall, because it is those conditions which lead to water supplies being contaminated”, he added.

The test could be crucial in preventing outbreaks of infection in families and communities, especially those using wells, private water supplies and groundwater schemes, Dr O’Connor said.

The research, funded by Environment Protection Agency, tested samples from wells, rivers, a turlough and a farm drain. Of samples tested 61 per cent were positive for the pathogen.

About 720,000 people – one in five households – depend on groundwater wells for drinking water, Dr Alfahl said. “But quality has been an issue as regulation is less stringent on these sources and testing is less frequent.”

Kevin O'Sullivan

Kevin O'Sullivan

Kevin O'Sullivan is Environment and Science Editor and former editor of The Irish Times