SYDNEY, April 28 (Xinhua) -- Australian scientists on Tuesday said they have developed new DNA tests to accelerate the detection of salmonella bacteria, potentially helping to pinpoint the source of major food poisoning outbreaks.
The "accurate and highly sensitive DNA tests … can identify the five most common salmonella subtypes in Australia", according to a University of New South Wales statement.
The tests detect the DNA "in as little as eight minutes" and "work at a constant temperature - unlike other methods that require specialized equipment for temperature cycling", it said.
Salmonella is one of the most common causes of foodborne disease worldwide, including in Australia, according to the university. The disease is usually characterized by acute onset of fever, abdominal pain, diarrhea, nausea and sometimes vomiting, with people catching it by consuming contaminated food of animal origin (mainly eggs, meat, poultry and milk), although other foods, including vegetables contaminated by manure, have been involved in its transmission. Person-to-person transmission can also occur through the fecal-oral route.
The latest study "overcomes the expensive and laborious traditional bacteria culture method and paves the way for fast-track testing directly from specimens", with the new tests, pending further research, offering the potential to help public health laboratories and industry curb the spread of future salmonella outbreaks.
The tests could play a critical role in quickly and accurately tracing the origin of future salmonella infections, according to the study's senior author Ruiting 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," Lan said.
"Salmonella, whether it's in a clinical or food sample - even in fecal matter - may exist in minute amounts and requires highly sensitive methods to detect."
The new DNA tests developed in the study were unique because the gene markers used were selected from analyzing thousands of salmonella genomes, he said.
"These markers are specific to the given serotypes and thus future-proof our new tests as traditional culture-based serotyping is being phased out," Lan said.
The team looked forward to continuing their research through field testing, he said. The latest findings were published in the Journal of Molecular Diagnostics.
"The test has been developed using pure cultures. It will need to be validated using samples in health, environment and food industry settings," Lan said.
"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," he said.
"Down the track, our tests could be used in clinical diagnosis in determining the common serotypes that cause Salmonella disease, to analyze trends of serotypes for public health surveillance, and they could also have application in the food industry." Enditem
