Evolution Of Microbes To Conquer And Colonize The Intestine

The study showing that bacterial sex driving evolution of microbes to conquer; and colonize the gut in the body. Bacterial sex drives evolution of microbes to conquer and colonize the gut. This discovery constitutes a paradigm shift and opens the possibility to design phage targeting therapies capable of dealing with the aftermath of infection and antibiotic usage, as well as antibiotic-resistant bacteria.

But as knowing bacterial colonization of the gut comes from studies with pathogenic bacteria in highly artificial laboratory models or disease contexts. Standard experimental models, which focus on infections with pathogenic bacteria and continuous antibiotic treatment, have not detected phage-driven horizontal gene transfer (HGT) and suggest that bacteria colonizing the gut evolve mainly through accumulation of mutations.

Evolution of microbes

In a surprising finding, the work of the IGC researchers now shows that HGT, not mutations, is the first evolutionary mechanism driving the pace and outcome of bacterial evolution in a healthy gut. Escherichia coliis a common colonizer of the human intestine as well as a potential pathogen. human intestine, this transfer of genetic material involves temperate bacteriophages (phages); viruses that infect bacteria and integrate into the bacterial chromosome as prophages, a process called lysogeny.

The colonization outcome is greatly influencing by different speeds; and modes of evolution of this opportunistic bacterium.E. colican evolve through mutations; which are then inheriting by daughter cells; or through a process of recombination, i.e. bacterial sex, in which genetic material is sharing between unrelated individuals. Prophages can later extricate themselves (and their genetic information); from the bacterial DNA and infect other bacteria in the gut microbiome.

Phage genetic material

Phages that are often classified as selfish reveal their altruistic side in the gut; providing a metabolic advantage to their bacterial host to conquer and colonize the gut. The phage genetic material that is transferring enables bacteria to gain access to specific carbon sources present in the gut; which providing a fitness advantage to phage carrying (lysogenic) invader bacteria.

But classical evolution model does not apply; and in fact horizontal gene transfer greatly overrides the contribution; of evolution through accumulation of mutations in the intestine of a healthy; With this work, we now understand better how evolution works in normal, healthy hosts. Phage driven HGT is a key eco-evolutionary driving force of gut colonization; it accelerating evolution and promotes genetic diversity of commensal bacteria.