Scientists at Cornell University have developed a rapid, less costly and sensitive new technique for detecting group A streptococcus, the bacteria that cause scarlet fever. The technique can be applied to a wide variety of bacterial pathogens, including E. coli.
The new biosensor works in a test tube and a positive result shows up as a red line on a strip, much like a pregnancy test. The method may help researchers and companies that are in the business of tracking food-borne pathogens, allowing technicians to determine a source quickly. It may also help to analyze a throat culture swab, to tell if someone has an illness like strep throat.
Current biosensors rely on a time-consuming technique called gene amplification that requires costly equipment. With the new technique, the entire process takes only 35 minutes, while traditional gene amplification techniques may take many hours. Early results suggest this new method could detect fewer than 100 cells of a pathogen in just half an hour.

“We hope to see this technique commercialized, because it is very rapid compared to all the standard methods right now,” said Sam Nugen, a graduate student in Cornell’s food science department and the study’s lead author. “It would be great if we came up with something that became a standard.”