Tuberculosis is ready to attack
Russian biologists declare dangerous evolution of tuberculosis
Biologists from MIPT and the Institute of General Genetics of the Russian Academy of Sciences declare the appearance of several thousand dangerous mutations in the DNA of tuberculosis bacillus, making it more resistant to the action of human immunity, according to an article published in the journal Genome Biology and Evolution (Mikheecheva et al., A Nonsynonymous SNP Catalog of Mycobacterium tuberculosis Virulence Genes and Its Use for Detecting New Potentially Virulent Sublineages).
"Humanity is trying to get ahead of the disease with the help of new drugs and technologies for treatment, but this fight has already been lost tactically. For fifty years, only one new antibiotic "Bedaquiline" with a new mechanism of action has been created. It has been used for about 2 years. But mycobacteria have already developed mutations of resistance to this antibiotic," says Valery Danilenko, an employee of the Institute of General Genetics of the Russian Academy of Sciences and Moscow Phys.Tech.
Tuberculosis is today, along with cancer and heart and vascular diseases, one of the main causes of death of people on Earth, especially in countries where HIV is widespread or there are unfavorable climatic conditions. The main means to combat tuberculosis today is the BCG vaccine, developed by the French Albert Calmette and Camille Guerin back in 1921.
Despite the lack of new vaccines and the widespread prevalence of tuberculosis throughout the World, BCG continues to protect the human body relatively effectively from Mycobacterium tuberculosis infection. The bacterium, as Western scientists believed, for some unknown reasons has not yet mutated so much that immune cells would cease to recognize it.
Danilenko and his colleagues found out that this is actually not the case by compiling a genetic atlas of all known strains of tuberculosis bacillus and discovering a new super-contagious and very dangerous subgroup of this bacterium by studying the genomes of microbes extracted from the bodies of Russians infected with HIV.
According to scientists, they managed to find and isolate 3,500 mutations in 319 genes of tuberculosis bacillus at once, which it uses to penetrate the human body and fight the immune system, some of which significantly simplify this task for the microbe.
These mutations, as noted by geneticists, are still found mainly in a single form in the DNA of 1.5 thousand strains of tuberculosis, which they managed to study. On the other hand, the combination of only three of the most dangerous of them made one of the strains of tuberculosis bacillus that currently exists in In Russia, Sweden, Belarus and Iran, it is very dangerous for people with weakened immunity.
The source of this bacterium, named B0/N-90, is one of the hospitals of the Samara region, from where it quickly spread across Russia and adjacent countries. Judging by the small differences in the DNA of representatives of this strain of tuberculosis from different parts of Russia, the bacterium mutates quickly, and its further evolution can become a big problem for people with weakened immunity and HIV-infected. This is already supported by the fact that the authors of the article found similar microbes with new mutations in the body of an HIV carrier from Irkutsk.
"Together with our colleagues from South Africa and We have prepared a project that will allow us to investigate the epidemiologically dangerous strain we have identified. The project is under consideration by expert communities of three countries, including the Ministry of Education and Science of the Russian Federation. We are trying to warn the international community and the relevant ministries of health of the BRICS countries about the impending danger. In the 80s, HIV appeared. Something similar can be expected with regard to new mutant strains of tuberculosis – a "Pandora's box" will open, – concludes Danilenko.
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26.04.2017