Discovery by scientists here may help fight against TB

Scientists here have discovered how certain bacteria evade the body's defences, paving the way for new ways to counter tuberculosis, and possibly a new generation of drugs to battle antibiotic resistance.

The Singapore-MIT Alliance for Research and Technology (Smart) researchers have discovered a new fundamental mechanism that controls when and how bacteria go into dormancy, a process which allows them to survive the host's immune response which would kill them.

"The ultimate goal is to cut down the time we need to treat TB," said Dr Chionh Yok Hian, 32, Smart Postdoctoral Associate and lead author of the paper. "More broadly, this allows the ability to target drug resistance, which is a growing concern worldwide."

The Smart scientists studied a type of bacteria known as Mycobacterium bovis, a weaker strain of TB used in the BCG vaccine.

Many bacteria, including the strains that cause TB, are able to enter a latent state which allows them to survive when deprived of oxygen or nutrients by the host's immune system. This dormant state also renders antibiotics ineffective.

By examining the changes in protein levels when mycobacteria are starved of oxygen, the researchers discovered a new mechanism that bacteria use in response to environmental changes.

Said Professor Peter Dedon, Smart Principal Investigator of the Infectious Diseases Interdisciplinary Research Group: "The basic genetic code determines what a cell makes. We discovered an alternative genetic code, very likely present in all bacteria, which assigns priority to the genes that are expressed.

"This enables the precise scheduling of gene products required to respond to starvation or to develop drug resistance."

This hidden code in the bacterium's genome enables the bacterium to alter which proteins it produces and in what quantities, allowing it to enter a latent state. The bacterium can potentially remain in this state for decades, reactivating once the host's immunity is compromised.

Based on its finding, Smart is working with Experimental Therapeutics Centre of the Agency for Science, Technology and Research, to develop new classes of antibiotics.

A version of this article appeared in the print edition of The Straits Times on November 12, 2016, with the headline 'Discovery by scientists here may help fight against TB'. Print Edition | Subscribe