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Have drug-resistant TB found a weak spot

Do tuberculosis bacteria have the gene, which you can use to overcome their resistance to drugs.

Tuberculosis still remains one of the most formidable diseases: for example, in 2015, according to statistics of the world health organization, there were an estimated 10.4 million infected with the TB bacterium, and about 2 million died from it. The causative agent of tuberculosis, M ycobacterium tuberculosis, and other bacteria that develops resistance to therapy, and the strains of M. tuberculosis that are not afraid of drugs, are increasingly found in human patients.


The causative agent of tuberculosis – the bacterium Mycobacterium tuberculosis. (Photo: Sanofi Pasteur / Flickr.com.)

Against drug-resistant tuberculosis have the means, for example, ethionamide. Itself ethionamide – no cure, however, it becomes a drug under the influence of the tuberculosis bacteria. From M. tuberculosis have the gene ethA, which encodes the enzyme that converts ethionamide to bacterial toxin and the cure usually accompany a special substances that stimulate this gene.

Ethionamide has become quite common with anti-TB medication, despite its side effects such as severe nausea, diarrhea, abdominal pain, etc. However, over time, there is a variety of M. tuberculosis with mutations in the gene ethA – mutant ethA bacteria acquired resistance to ethionamide, too.

The staff of the French National center for scientific research, Lille University, Institut Pasteur, Karolinska Institute and many other research centers have found a way to overcome such resistance tuberculosis strains. In an article in Science , researchers write that M. tuberculosis in fact there is another enzyme that can make ethionamide poison, and only need to “Wake up” gene ethA2 in which this encoded alternative enzyme.

The authors describe the substance SMARt-420 – molecule activator for ethA2: experiments showed that ethionamide in the company of the activator effectively acts as the normal strains of the pathogen of tuberculosis and drug-resistant. In mice after this double medication the number of bacteria in the lungs was reduced by 40 000 times, and as a result, germs have become the same as in the treatment of conventional anti-TB antibiotics to mice with normal strains of the microbe. Moreover, given that side effects of ethionamide are pretty nasty, SMARt-420 can be optimized ethionamide therapy, because the new Supplement makes the bacteria much more sensitive to this medicine.

Of course, as writes portal Science, there is a chance that bacteria will have a resistance to SMARt-420. So it didn’t happen, the authors suggest to use a molecule-activator with interruptions: if the bacterial population and there will be cells with a new resistance, their first is too small, so then when SMARt-420 will temporarily disappear, they will eventually replace standard tuberculosis germs. So it manages simultaneously to destroy those who are simply not sensitive to ethionamide and other drugs, and to prevent the emergence of resistance “new generation”.

However, as it is better to use a SMARt-420, will become clear after clinical trials, which should begin in a year and a half.

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