Scientists in Russia have discovered how tuberculosis-causing bacteria protect themselves from antibiotics. The finding could help improve treatments for drug-resistant forms of the disease, according to the press service of Perm National Research Polytechnic University.

Russian researchers identified a mechanism that allows tuberculosis pathogens to defend themselves against antibiotics. The discovery will make it possible to refine treatment methods for resistant forms of tuberculosis, the university’s press service told TASS on World Tuberculosis Day, observed on March 24.

“Scientists from Perm National Research Polytechnic University and the Institute of Ecology and Genetics of Microorganisms of the Ural Branch of the Russian Academy of Sciences have determined exactly how tuberculosis pathogens protect themselves from drugs. If this mechanism is blocked, the bacterium will begin to destroy itself. The discovery will help create medications that restore the effectiveness of existing antibiotics in fighting resistant forms of tuberculosis.”

The tuberculosis bacillus belongs to microorganisms capable of developing resistance to antibiotics. Forms of tuberculosis have already emerged worldwide that are resistant to two of the most effective drugs, rifampicin and isoniazid. For this reason, researchers are studying bacterial defense mechanisms to find vulnerabilities and target them with new medications.

The researchers tracked changes in the tuberculosis bacillus cell under the influence of antibiotics using Mycobacterium smegmatis, a non-pathogenic bacterium closely related to the tuberculosis pathogen. When exposed to drugs, the bacteria stopped consuming cysteine, an amino acid essential for growth, and began accumulating it. In large amounts, cysteine becomes toxic, yet the cells did not die. This was due to a mechanism that packages excess cysteine into a special substance called mycothiol.

“The more toxin accumulates in the cell, the more actively the defense mechanism is triggered,” explained Galina Smirnova, a leading researcher at the laboratory of physiology and genetics of microorganisms.

Mycothiol was previously known for protecting bacteria from external stressors such as antibiotics and oxidative stress. It turns out its role is broader: it also helps neutralize internal toxins formed within the cell. This discovery may enable the development of targeted treatments specifically against the pathogen.

“If mycothiol synthesis is blocked, the bacterium will lose its ability to hide toxic cysteine. It will have to urgently convert it into hydrogen sulfide and release it outside. But this process requires enormous energy expenditure — the cell will begin to suffocate, lose the ability to maintain vital processes, and ultimately die from its own toxin,” explained Lyubov Sutormina, an assistant at the Department of Chemistry and Biotechnology.

World Tuberculosis Day is observed on March 24. On this day 144 years ago, German scientist Robert Koch announced the discovery of the bacterium that causes the disease, now known as the Koch bacillus. Since then, humanity has developed vaccines, antibiotics, and early diagnostic methods for tuberculosis, yet the disease remains one of the leading causes of death from infectious diseases worldwide.

Source: TASS, March 24, 2026.