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DNA technology used to detect harmful bacteria in drinking water

Scientists at SA Water’s Australian Water Quality Centre (AWQC) are applying cutting-edge DNA technology to identify potentially dangerous bacteria in water sources. 

Detecting and treating E.coli in waterways has become more difficult in recent years, due to the proliferation of a new kind of bloom E.coli. This doesn’t pose a risk to human health but can hide the presence of its more dangerous counterparts.

“We’re not sure why – it could be climactic – but water conditions are changing across Australia and we’re getting these bloom E.coli,” AWQC Method Development Coordinator Gary Hallas said. 

“These are the main indicators for water utilities and they have the potential to mask fecal E.coli in a reservoir.”

Water is tested using the Ion Chef DNA sequencing system, which creates a DNA ‘soup’ from the sample and attaches a barcode to the different DNA within it. This is connected to a different machine, which reads the data and sorts the harmful from the harmless bacteria.

Although the technology is well developed in the medical world, Hallas said SA Water is the first to use it to sequence specific E.coli DNA.

“It’s new for the water industry to be able to very clearly delineate the bloom E.coli that is occurring versus fecal E.coli, to the point where we can even tell what animal the E.coli has come from,” he said.

But the technology has much wider application than E.coli detection. It can also be used to identify the presence of fish and vertebrates, and Hallas said he is interested to see how it will evolve within the water sector.

“I think over time people will see there are so many different ways you can use it,” Hallas said. 

“It will give you so much more knowledge to protect the public.”

Learn more about SA Water’s next-gen methods for identifying bacterial contaminants: