New molecules that reveal cough mucus and active TB in saliva can simplify TB diagnosis and speed up detection of drug-resistant strains of the drug.
This synthetic molecule is a modified version of the sugar that is consumed by the TB bacterium to help build cell walls. The sugar is stained with a dye under a fluorescent microscope – but only when the dye is not surrounded by water. On February 28, scientists reported in the journal Science translational medicine, called DMN – Tre hybrid molecules in the dark until it into a fat in the cell walls of n/med tuberculosis bacili, waterproof, and began to shine.
Standard test used dye dyeing a bunch of different bacteria, so the technical personnel must be apart from TB cells all dye bleaching, imperial college London, TB researchers Sumona Datta, said he was not involved in the work. But this chemical wash is time-consuming and error-prone. Because dmn-tre shines only when TB or its near relatives are swallowed, the molecule can provide a simpler, more reliable diagnosis, she said.
According to the world health organization, 1.7 million people died of tuberculosis in 2016. Rampant resistance to drugs makes the disease harder to fight.
Carolyn Bertozzi, a chemical biologist at the Howard hughes medical institute at Stanford university in the United States, and colleagues tested the new molecule’s destruction of 16 sputum mixtures with tuberculosis. After a few minutes, the molecules tagged the TB microbe in the sample, and it showed the number of bacteria similar to the standard staining technique – no problem with chemical washing after dyeing.
“It’s very impressive,” said jiang hongrao, a chemist and radiologist at Stanford university, who was not involved in the work. But he said the dmn-tre needed to be tested in larger clinical trials before it could enter prime time.
New TB screening techniques may also have an advantage in examining whether patients respond to treatment, says harvard microbiologist Eric rubin. Because molecules glow only when eaten by healthy, hungry TB bacteria, they do not mark the microbes that have been left or killed by antibiotics like a typical test. So if there are still a lot of hot microbes in the sputum of patients treated with antibiotics, doctors will know to try different drugs.
While the current drug resistance tests may take weeks or months, dmn-tre shows how the bacteria that are treated within a few hours can develop. “It’s very exciting,” said Carlton Evans, a TB researcher at imperial college London who was not involved in the study. Rapid drug resistance testing (SN Online: 12/7/14) can help researchers predict which antibiotics are best for TB.