Currently, a method called GeneXpert, can accurately
detect Mycobacterium tuberculosis DNA within a couple of
hours, but it requires specialised equipment and trained
personnel, making it impractical for rural areas or developing
Chemist Jianghong Rao of Stanford and microbiologist
Jeffrey Cirillo of Texas A&M Health Science Center in Bryan
have developed a chemical called CDG-3, which glows when it is
broken down by an M tuberculosis enzyme called BlaC.
The researchers found that they could detect as few as
ten bacteria in a millilitre sample, 'nature.com' reported.
They then tested the method on 50 sputum samples from
people in Texas.
It correctly identified all the samples that contained M
tuberculosis visible under a microscope, and 80 per cent of
those in which infections were not visible.
When tested in people without TB, the CDG-3 probe
diagnosed them correctly 73 per cent of the time.
Rao and Cirillo are now working with diagnostics company
GBDbio in Temple, Texas, to develop a portable,
battery-powered device that measures the fluorescence coming
from CDG-3 as it is broken down.
Chief executive Michael Norman said that the company
hopes to have the device completed and on the market in 2015.
He expects that a single test will cost about USD 5, and
will take less than 30 minutes to deliver a diagnosis.