Gram-positive bacteria

Researchers from McMaster University have developed a new diagnostic test that can easily and quickly identify dangerous pathogens and infectious diseases such as hepatitis C.

The method can detect any compound that might signal the presence of an infectious disease, regardless of whether it is respiratory or gastrointestinal.

Specifically, the method is capable of detecting the smallest traces of metabolites, proteins or fragments of DNA.

McMaster Biointerfaces Institute director John Brennan said: "The method we have developed allows us to detect targets at levels that are unprecedented.

"The method we have developed allows us to detect targets at levels that are unprecedented."

"The test has the best sensitivity ever reported for a detection system of this kind. It is as much as 10,000 times more sensitive than other detection systems."

The scientists used sophisticated techniques to develop a molecular device made of DNA that can be switched ‘on’ by a specific molecule of their choice, such as a certain type of disease indicator or DNA molecule representing a genome of a virus.

The action leads to a massive, amplified signal that can be easily spotted. The test does not require complicated equipment and can be run at room temperature under ordinary conditions.

McMaster Departments of Biochemistry and Biomedical Sciences, Chemistry and Chemical Biology professor Yingfu Li said: "This invention will allow us to detect anything we might be interested in, bacterial contamination or perhaps a protein molecule that is a cancer marker.

"Our method can sensitively detect all of them, and it can do so in a relatively short period of time."

Scientists are currently working to move the test onto a paper surface to create a portable point-of-care test, which would completely eliminate the requirement for lab instruments, enabling family physicians to run the test.

The Biointerfaces Institute has developed a series of paper-based screening technologies that helps users to generate clear, simple answers that appear on test paper indicating the presence of infection or contamination in people, food or the environment.

Image: Gram-positive C difficile bacteria from a stool sample. Photo: courtesy of Janice Carr, Centers for Disease Control.