A new, interesting discovery made by a group of researchers from two Australian institutions was published today in the ISME Journal. According to the researchers, the bacterium Mycobacterium tuberculosis, which is responsible for tuberculosis in humans, can survive in the human body by “feeding” on carbon monoxide.
The latter is a gas that is notoriously dangerous just for humans as it can cause death in no time. For several microorganisms, including many species of bacteria, this gas is instead a source of energy. As one of the authors of the study, Chris Greening, a researcher at Monash University, explains, some pathogens use carbon monoxide to stay alive when other nutrients cannot be found.
Among them are mycobacteria, a group of bacteria that can cause various diseases in humans, including tuberculosis, leprosy and Buruli ulcer. When they infect the human body, for example, they usually find a hostile environment in which there are few nutrients.
Precisely for this reason they resort to carbon monoxide, as explained by Paul Cordero, another author of the study: they break down the gas, produced in very small quantities by immune cells in humans, into those that can be considered its fundamental components and are able to provide the energy to their cells to continue living during essentially “dormant” phases, phases that can allow them to remain alive inside the bodies even for years.
They do this thanks to an enzyme called carbon monoxide dehydrogenase, an enzyme that basically allows bacteria to produce energy from this gas. The latter does not prove sufficient to allow for real growth but still allows them to survive during the initial stages of infection.
As Katie Bayly, another author of the study, remembers, it was already known that Mycobacterium tuberculosis uses carbon monoxide, but it was not known why and no one knew how.
Now that we know that these bacteria use carbon monoxide to resist during the initial stages of infection in human lungs, it may be possible to propose new, more targeted therapies to defeat tuberculosis.