Scientists have developed a new test that can easily and quickly identify bacteria in any liquid, such as water, milk, or urine. This test uses a type of virus that only insects bacterial cells, called a bacteriophage, which is embedded in a gel. It may improve diagnostic efforts and food safety by revealing the presence of pathogens like Listeria or E. coli even at low levels. The test shows when bacteria are present with a color change.
A bacteriophage or phage specifically infects one type of bacterium, and when they attack a bacterial cell, the cell breaks open and bits of it spill out. In this new test, these microscopic bacterial molecules trigger a color change that can be easily seen. If no bacteria are present, there is no color change. This test can be performed in only a few hours, which is much less time than a culture test that typically needs two days to generate results. The research has been published in Advance Materials.
“We’ve been using phages’ destructive power to kill bacteria and resolve infections for years,” said co-corresponding study author Zeinab Hosseinidoust, an associate professor at McMaster University. “Here, we’re chanelling 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.”
It takes several days for people who suspect that they have a urinary tract infection (UTI) to receive results of a diagnostic test, noted co-corresponding study author Tohid Didar, an associate professor at McMaster. But this new test can be used to test clinical samples as well as environmental and food samples. People may even be able to test themselves at home for things like UTIs, noted Didar.
The researchers validated the test using urine samples from volunteers, and water samples. The test worked accurately, and was as good as lab tests at diagnosing patient infections, and could accurately identify E. coli contamination in lake water.
The test can also be adapted to identify many other kinds of bacteria, including Salmonella.
“Phages can knock on every biological door, but they will only enter the ones they are programmed to find,” said study co-author Carlos Filipe, a professor of chemical engineering and a senior authior on the paper. “That specificity is a huge advantage for quick and precise detection, even at low levels.”
Sources: McMaster University, Advanced Materials