Selective targeting of bad bugs in the gut may have many health benefits

We live among microbes that preceded us on Earth by a few billion years. As new kids on the block, we are hosts to more than thirty trillion bacterial organisms per person, not far from the total number of cells in the human body. Most commensal bacteria reside in our intestines where they are not only benign but also do useful things like help extract nutrients from food and protect us against pathogens. When these complex communities are disrupted by external perturbations such as exposure to broad-spectrum antibiotics or radiation treatment, health problems arise. One well-known condition where dysbiosis leads to overgrowth of toxin-producing bacteria is C. difficile infection, an often-lethal disease of the colon caused by an unquestionably bad bug. Gut dysbiosis can also cause distal health problems, including some neurological conditions, through what is known as the gut-brain axis. Restoring healthy gut microbiome by highly selective targeting of pathogenic bacteria may remedy multiple conditions where microbial toxins and metabolites contribute to pathology. Promoting robust, symbiotic microbiome diversity turns out to be good not just for bacterial gut communities but also, through maintenance of colonization resistance, for their evolutionarily much younger hosts.