New Hands-Free Rapid Test Detects Bacteria in Fluids

Bacteriophages, the most abundant form of life on Earth, are specialized to target and destroy specific types of bacteria. Their natural ability to fight bacteria has long been harnessed to treat infections. Now, researchers have developed a novel test that uses harmless bacteriophages to detect disease-causing bacteria in fluids. This test enables even untrained users to identify bacterial contamination in liquids using a biogel that changes color when exposed to bacteria like E. coli, listeria, and other common pathogens.

The test, developed by a team of engineers and biochemists at McMaster University (Hamilton, ON, Canada) utilizes bacteriophages embedded in a gel to detect bacteria in fluid samples, including urine, even at low concentrations. In the test, the bacteriophages target and attack specific bacteria in the sample. As the bacteria are destroyed, they release small amounts of intracellular material that the test can detect, causing the gel to change color. If no bacteria are present, the color remains unchanged. This process takes just hours to provide results, significantly faster than traditional lab cultures, which can take up to two days. The test, detailed in a paper published in Advanced Materials, is part of a broader effort by researchers to develop simple technologies accessible to consumers, medical professionals, and industries.

Image: A new test finds bacteria in liquids and indicate their presence by changing color (Photo courtesy of Georgia Kirkos/McMaster University)

The team had previously worked on creating a portable library of tests using phages to combat antibiotic-resistant infections. To validate the new test, the researchers used urine samples from patients at Hamilton Health Sciences, and the results were consistent with those of traditional lab methods. This new test can be customized for any bacteria by utilizing specific bacteriophages and DNA probes targeting microbes like listeria and salmonella. The ability to test complex fluids, such as blood and urine, for contamination is particularly challenging, and the simplicity and reliability of this new test make it a valuable tool. The researchers hope to collaborate with commercial partners to bring this innovation to the market.

“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 tests themselves at home and get a result in a matter of hours,” said corresponding author Tohid Didar, an associate professor of mechanical and biomedical engineering who holds the Canada Research Chair in Nano-Biomaterials.