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DNA test could offer faster, cheaper salmonella testing

salmonella bacterium

SALMONELLA testing could be completed faster in future if a promising new detection method proves commercially viable.

Researchers at Australia’s University of New South Wales have developed a DNA test that can rapidly detect several serotypes of salmonella in as little as eight minutes.

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It could prove more efficient than current bacterial culture-based sampling methods, which are more time consuming and costly.

The Multiple Cross Displacement Amplification (MCDA) method has already proven successful at detecting salmonella but has not until now been able to distinguish different subtypes of the bacteria.

This work was able to develop tests for the most common serotypes in Australia: S. Typhimurium, S. Enteritidis, S. Virchow, S. Saintpaul and S. Infantis.

‘Essential’

While more validation work is needed – in particular as the strains used so far have been pure samples – the work was promising, according to senior study author Ruitling Lan.

“It is essential for public health investigators to have a fast, simple way of tracking down the source of salmonella outbreaks – so, the ability to test for different types of salmonella is important,” Prof Lan said.

“Salmonella, whether it’s in a clinical or food sample – even in faecal matter – may exist in minute amounts and requires highly sensitive methods to detect.

‘Tiny amounts’

“Our enhanced Multiple Cross Displacement Amplification (MCDA) method can detect tiny amounts of DNA rapidly and at a constant temperature, which makes it an excellent fit for a simple, rapid and sensitive bacterial detection test.”

Prof Lan added: “It’s difficult to know when our tests would become available, but they are part of the global trend towards culture-independent diagnostic tests which can identify the bacteria causing a foodborne illness without the need to culture the bacteria in a lab.

In 2017, more than 16,000 cases of Salmonella poisoning were reported in Australia – a 30% increase on the previous 10-year average. The rate is estimated at 185 cases per 100,000 people, per year.

The research was published in the Journal of Molecular Diagnostics.