we need, then, are personalised infusions. We cannot expect the same probiotic strains, or the same donor stools, to treat a variety of diseases. A better approach would be to customise probiotics according to the ecological vacancies in an individual’s body, the quirks of their immune system, or the diseases that they are genetically vulnerable to.49 Doctors will also need to treat both the patient and their microbes at the same time.
