Faced with the challenge of antibiotic resistance, scientists are increasingly interested in bacteriophages, the viruses present in our intestines, because some viruses could well be good for the body.
the microbiome is defined as all the micro-organisms living on the surface and inside the body. It contains bacteria but also viruses and fungi. Today, thanks to the emergence of new advanced technologies and to find alternatives to antibiotic resistance, scientists are beginning to focus on the virome or mycobiome, since viruses are installed in various niches of the human body such as the inside the nose and the intestinal mucosa. It is moreover in the intestinal virome that the greatest number of viral occupants have been identified. Scientists consider the virome to be “the largest, most diverse, and most dynamic part of the microbiome,” and most of the viruses in our gut are bacteriophages. Where there are bacteria, there are bacteriophages. These infect bacteria and use their cellular machinery to replicate their genetic material.
From the 1920s to the 1950s, scientists tried to understand whether bacteriophages, capable of destroying human pathogens, could also treat bacterial infections. They then discovered that bacteriophage therapy was effective and without side effects. Then, when the antibiotics arrived, this technique took a back seat. But now with the growing emergence of antibiotic resistance on a global scale, researchers are looking for alternatives and are once again interested in phage therapy.
It interests them above all for its specificity. Because, while antibiotics eliminate a wide spectrum of bacterial species, some of which are “good”, bacteriophages only target a narrow range of strains within the same bacterial species. They only attack the bacteria they want and continue to replicate until they have eradicated the infection. Conversely, sometimes bacteriophages are beneficial for populations of bacteria.
What is the role of bacteriophages in intestinal diseases?
When a phage becomes active, it can wipe out communities of bacteria, which potentially allows bad bacteria to fill the void and can lead to microbial imbalance. This can be associated with conditions such as inflammatory bowel disease, colitis, obesity, or even chronic fatigue syndrome.
However, researchers aren’t sure whether bacteriophages are responsible, because while they cause changes in the gut, these aren’t always the cause of the disease. Indeed, bacteriophages could on the contrary be passively modified by changes in intestinal bacteria.
Until now, scientists have been unable to study the virome because viruses have no equivalent genes between species. But now, advances in next-generation sequencing are enabling breakthroughs. While less is still known about the role of viruses in health than in disease, it seems highly likely that they also play a role in a healthy body. Although viruses are best known for causing disease, some of them are of no interest to human cells.
The global consumption of antibiotics has exploded in fifteen years
But given the international community’s concern about antibiotic resistance, the renewed interest in bacteriophage will undoubtedly encourage more researchers to take an interest in the subject, it must be recognized that, given the complexity of the composition of the microbiome, the task promises to be difficult. “The composition of the intestinal microbiome is not the same during the different stages of life, or even during the hours of the same day”, explain the scientists. And of course, each individual has their own microbiome, bacteria and bacteriophages.
Between 2000 and 2015, global antibiotic consumption increased from 21.1 billion daily doses to 34.8 billion, an increase of 65%. However, only countries with middle or low income (LMIC) have greatly increased their consumption of antibiotics (+114% in 16 years). For example, the use of antibiotics has increased by 50% in India, 79% in China and 65% in Pakistan. Thanks to awareness campaigns, it is, on the other hand, relatively low (+ 6%) in high-income countries (HIC). In France, it has slightly decreased in recent years, especially among young people, according to a recent report by Public health France. France, however, remains quite a poor student since it remains the third least efficient country in Europe in this area behind Greece and Cyprus.
