Developed by engineers and biochemists at McMaster University in Canada, the test has been developed for use by non-specialist users.
The test uses bacteriophages embedded in the gel to locate target bacteria in a sample of fluid such as lake water, urine or a container of milk, even in low concentrations.
Bacteriophages are the most abundant form of life on Earth. Also known as phages, bacteriophages are viruses that infect and replicate only in bacterial cells.
In the test, phages find and attack the target bacteria in a sample, causing the bacteria to release microscopic amounts of intracellular material which the test can read, triggering a visible colour change. If the sample is clean, the colour stays the same.
The new process takes hours, producing results more quickly than lab cultures, which can take two days to generate results.
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In a statement, Zeinab Hosseinidoust, an associate professor of biomedical and chemical engineering, said: “We’ve been using phages’ destructive power to kill bacteria and resolve infections for years. Here, we’re channelling that power in another way. Because phages can burst bacteria open, they can give us quick access to the biological components of those bacteria that we use to confirm their presence.”
The test, described in Advanced Materials, is said to be the latest in a series of technologies the group has developed that are aimed at placing simple technology within reach of producers, retailers, consumers and medical professionals.
“Now we have a tool that can be used in food samples, environmental samples and clinical samples,” said corresponding author Tohid Didar, an associate professor of mechanical and biomedical engineering. “Today, people who suspect they may have a urinary-tract infection must visit a doctor and sometimes wait days for a result. This technology would make it very easy for people to test themselves at home and get a result in a matter of hours.”
The group’s previous work includes creating a portable testing library to match phages to otherwise untreatable antibiotic-resistant infections, a contamination test incorporated into food packaging, and a temperature-stable storage system for live vaccines.
The group confirmed the concept of their newest test using urine samples from patients at McMaster affiliate Hamilton Health Sciences, and in all cases results from the experimental test produced the same results as traditional lab tests. The test also worked to detect E. Coli in lake water samples.
According to the University, the new test can be adapted to any bacterium by using bacteriophages and DNA probes that target microbes such as listeria and salmonella.
“Phages can knock on every biological door, but they will only enter the ones they are programmed to find,” said Carlos Filipe, a professor of chemical engineering and a senior author on the paper. “That specificity is a huge advantage for quick and precise detection, even at low levels.”
Such a test could have provided early and accurate detection in the recent listeria contamination of plant-based milk that killed two, made 10 ill and caused wide recalls in Canada, the researchers said.
“This technology could be helpful in rapidly limiting outbreaks,” says co-author Akansha Prasad, a Vanier Scholar and PhD student in biomedical engineering. “If you had something in your fridge that you were concerned about, this test could let you know if it was safe for consumption.”
Testing for contamination in complex fluids such as milk, blood or urine is especially challenging, making simple, reliable alternatives such as the new test very useful, said the researchers who want to work with commercial partners to bring the technology to market.
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