Discovery of slow-growing TB bacteria may pave way for new drugs

Washington, March 30 (ANI): Scientists have found a large number of slow-growing Mycobacterium tuberculosis bacteria in the lungs of TB patients, which can pave the way for new medicines for treating the disease.

Dr Simon Waddell and his colleagues, from St George's University of London and the University of Leicester, point out that scientists have always thought that M. tuberculosis bacteria in the lungs of TB patients are rapidly multiplying.

However, the researchers add, when they used gene chips to look at how TB bacteria behave in different environments, they observed that the bacteria in the sputum-phlegm coughed from the lungs-of patients with the disease resembled bacteria that are growing very slowly or hardly at all.

The researcher said that the finding has caused concern because slowly growing bacteria are non-responsive to treatment with isoniazid, one of the main antibiotics used to treat TB.

According to them, this may be the reason why it takes six months to treat pulmonary TB successfully, while most bacterial infections are treated in days.

The team further point out that the prolonged treatment often causes patients to stop taking their medicines early or to take them intermittently, which can cause relapses and the emergence of antibiotic resistance.

"Our observations imply that either a large number of the infecting bacteria in the lungs are not multiplying rapidly as previously suggested; or the bacteria are adapting by not growing when they are coughed from the lungs into the air," said Dr Waddell.

"We need to find out how bacteria respond during infection and after drug treatment to understand how bacteria become tolerant to antibiotics. This will provide alternative opportunities for the development of better drugs that the world desperately needs to combat the growing health threat of TB," he added.

Waddell presented his team's findings at the Society for General Microbiology meeting at Harrogate on March 30. (ANI)