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The Story of a Microbiota That Became a Medicine
Once upon a time, in the hospitals of the twenty-first century, there was an infection that even antibiotics could no longer silence. An opportunistic infection caused by a bacterium called Clostridioides difficile, it often appeared in patients who were already vulnerable… and, above all, already heavily treated. Let us look back at the history of this infection, which gave rise to new therapeutic approaches.
It always begins with another infection, treated in an entirely conventional way with antibiotics. A logical, effective, almost routine response. But these treatments have a collateral effect that we sometimes forget: antibiotics are true microbiological napalm. They do not only destroy the bacterium responsible for the infection; they also wipe out a large part of those discreet bacteria that, every day, help maintain intestinal balance. The ecosystem becomes depleted, its balance is disrupted, and the species that had occupied the terrain disappear.
This is when Clostridioides difficile finds its opportunity. Taking advantage of this weakened intestine, of the space that has been left vacant, it settles in, proliferates, and triggers a new infection. Then the routine resumes. It is treated with antibiotics, notably vancomycin. It disappears, then comes back. Relapses follow one another, eventually leading to a genuine therapeutic dead end: a C. difficile infection that becomes increasingly difficult to control.
It was in this context that clinicians began to look at this infection differently. What if the real problem was not only the bacterium itself, but also the environment in which it was proliferating? What if, instead of continuing to bombard the intestine, it was necessary to repopulate it?
Following this line of thought, the Dutch team led by Els van Nood published a study in 2013 in the New England Journal of Medicine that would leave a lasting mark on the history of the microbiota. In patients suffering from recurrent C. difficile infections, fecal microbiota transplantation proved more effective than vancomycin at preventing relapse. For the first time, it was clinically demonstrated that by restoring a microbial community, one could treat a disease.
In reality, the idea was not entirely new. As early as the fourth century in China, the physician Ge Hong had already described the use of fecal preparations, sometimes referred to as “yellow soup,” to treat severe diarrhea.
Be that as it may, the success of Els van Nood’s team profoundly changed perspectives. The microbiota was no longer merely a biological backdrop, background noise, or a simple marker of health status. It became a therapeutic target in its own right. Attention was no longer focused solely on the pathogenic bacterium, but also on the ecosystem that it had disrupted, or from which it was benefiting. The logic had shifted sides: sometimes, in microbiology, one does not heal better by eliminating, but by restoring.
From that point onward, a new ambition emerged. Could we go further than fecal transplantation? Could we identify key species, understand their functions, standardize preparations, and better control their composition, quality, and reproducibility? In other words, could this ecological intuition be transformed into a rational, pharmaceutical therapeutic approach?
This is how Live Biotherapeutic Products, or LBP, gradually emerged: products containing living microorganisms, developed to prevent, treat, or relieve disease, with characterization, manufacturing, and quality-control requirements worthy of a medicinal product.
Today, this momentum extends far beyond the sole context of Clostridioides difficile infections. Microbiota-based approaches are becoming more structured, more standardized, and are now being developed in other clinical settings, particularly in hematology and oncology, where the state of the intestinal microbiota strongly influences treatment response.
In the end, the history of microbiotherapies reminds us of one essential fact: in microbiology, living systems can never be reduced to a single species. Everything is a matter of interactions, balance, and coexistence. And sometimes, to fight one bacterium, it is enough simply to bring back to life all that had until then prevented it from taking over.
See you soon for the next episode of Smaltis’Story!