SA Water scientists’ new forensic tech tackles climate change bugs in Aussie waterways

SA Water scientists from the Australian Water Quality Centre (AWQC) laboratories are using cutting-edge DNA technology to quickly differentiate between climate-influenced non-infectious bacterial blooms and potentially dangerous E. coli bacteria, to help maintain public health and safeguard Australia’s water supplies.

A common bacterium found in human faeces, E. coli has long been a potential contaminant to waterways and catchments, posing a risk for gastrointestinal illness if not detected and treated by the effective measures implemented by SA Water and other utilities.

This practice has been made more challenging for water treatment operators over recent years with the proliferation of a different, potentially climate-evolved bloom E. coli, which does not pose a risk to human health but can mask its more dangerous counterpart.

Speaking ahead of today’s OzWater ‘19 conference in Melbourne, AWQC’s Method Development Coordinator Gary Hallas said developing new methodologies and harnessing progressive technology is vital to staying on top of bacterial evolution.

“The prevalence of thermotolerant bloom E. coli has been an increased issue for water utilities across Australia, which we speculate is potentially due to Australia’s changing climate and water conditions, allowing for an evolution link and gene transference mechanism between common bacteria in our open water sources and our indicator organism for risk management,” Gary said.

“We use a number of barriers and treatment options to deliver safe, clean drinking water every day to our customers, and it is vitally important for health protocols to have an ability to pinpoint between harmful and non-harmful E. coli samples should they ever arise.  

“Through a new thermotolerant culturing process and then identifying the unique E. coli DNA sequence-types, we can clearly differentiate the make-up of both naturally blooming and potentially pathogenic faecal E. coli within just a few hours, and most importantly, if any samples are of human health concern.

“This is ground-breaking research for water quality management in Australia, as despite not posing risk to the human body, non-faecal E. coli has the potential to mask a true contamination event should it ever arise.

“These types of events are becoming more common across Australia with ever changing climatic and water matrix conditions across Australia. New DNA technology advances are being employed at SA Water to assist the water industry understand this new phenomenon.”

The method utilises a unique thermotolerant agar culture developed by Gary Hallas and the AWQC. Using the ION Chef and the ION S5 analytical equipment, the DNA from the samples is placed on a DNA chip with unique barcodes identifying the problematic E. coli found in water samples, which provides more detailed and reliable information than ever provided before in routine use by water laboratories around Australia.

“Much like tracing a DNA fingerprint, we can also use the ION chef and ION S5 to identify unique characteristics in the water samples, which allows us to track and monitor its presence over time at a single location or its movement through the network,” Gary said.

“We are the only water utility in the country regularly using this software to sequence specific E. coli DNA, and SA Water is at the forefront in helping other utilities across the water industry to identify and manage blooms in their water sources to prevent potential waterborne illness.”  

A business unit of SA Water, AWQC provides world-leading specialist water and sewerage expertise including sampling, analysis, advice and research to other Australian and international water companies.

‘Thermotolerant MI Agar and Whole Genome Sequencing for differentiation of faecal contamination from bloom events’ will be presented at OzWater’19 – Australia’s international water conference and exhibition – on Wednesday 8 May between 10:45am – 12:15pm at the Melbourne Convention Exhibition Centre.

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