There tuberculosis, scourge of the 19the century, could it become the new scourge of the 21st?e century? This infectious disease, which mainly affects the lungs, has never been eradicated. Its progression has slowed considerably thanks in particular to the BCG vaccine (Calmette and Guérin bile vaccine). But this vaccine does not completely prevent infection and transmission of the bacteria. Mycobacterium tuberculosis, responsible for the disease.
So the microbe continues to circulate, causing million new cases each year, including more than a million deaths. This circulation even tends to increase, with a rebound in France in 2023. In addition to the vaccine, there are also antibiotics against this pathogen. But strains resistant to all these treatments are spreading, according to a study published on 1er January 2025 in the New England Journal of Medicine by researchers from the Swiss Tropical and Public Health Institute and the National Center for Tuberculosis and Lung Diseases in Georgia, a country heavily affected by the disease.
A quarter of tuberculosis strains are highly resistant to antibiotics
The authors analyzed the genomes of the bacteria Mycobacterium tuberculosis found in nearly 7,000 patients in Georgia. A small proportion of these strains (60) had genetic mutations that conferred resistance to almost all available antibiotics. Genetic analysis shows that a quarter of These sixty resistant strains (16) came from only four different strains. That is to say, these difficult-to-treat bacteria can be transmitted from one patient to another, and that four patients would have transmitted these four different strains to approximately three other patients each.
This transmission of antibiotic-resistant strains was confirmed with data from around the world. The authors analyzed more than 80 million genomes of this bacteria, identifying more than 400 strains highly resistant to antibiotics, in 27 different countries. The country with the most cases of antibiotic resistance is India, followed by South Africa and Georgia. The good news is that the total number of cases is still low., states in a press release Galo A. Goig, author of the study. But it is worrying to note that a quarter of these strains that are highly resistant to antibiotics come from transmission from one patient to another."
Some of the strains are resistant to all currently used antibiotics.
Nearly a quarter (117) of these bacteria came from only about 40 strains. That is, each original patient in whom this antibiotic resistance emerged passed the bacteria on to about two other people. Even more serious, nine of the strains identified had resistance to all currently available antibiotics. These fully antibiotic-resistant bacteria were identified in Belarus, Georgia, India and South Africa.
Highly resistant strains can become fully resistant
According to the genetic study, none of these fully resistant strains were identical to any other. That is, there was no direct transmission of one of these strains from one patient to another. But about half had a strong genetic link, which suggests that the transmission took place before, when the strain was only resistant to some of the antibiotics. And it was after this transmission that the strains continued to evolve, developing the missing resistances.
According to the authors, this highlights the danger of allowing transmission of partially resistant strains, which can later become fully resistant.This example shows how antibiotic resistance is one of the most serious threats to health in the world today., recalls Sébastien Gagneux, director of the study. We must stay ahead of the race between the design of new treatments and the emergence of resistance, we must do everything to avoid entering a post-antibiotic era. (where antibiotics are no longer effective, editor's note), both for tuberculosis and for other infectious diseases.”
English 
French