Fecal microbiota transplantation – where are we?

In addition to its antimicrobial protective role, the gut microbiota affects human metabolism and immunity as well as inflammatory and neuro-hormonal responses. Due to its beneficial effects on health even up to the genetic level, it is referred to as a “forgotten organ,” “virtual organ,” or “other brain” (1). The human gut microbiome differs among individuals and usually does not change over time. Its composition is affected by several environmental factors (1-3). Fecal microbiota transplantation (FMT) or bacteriotherapy (health donor stool transplantation) is the instillation of a fecal suspension taken from a healthy donor into the upper or lower gastrointestinal (GI) tract of a patient, with an aim to enrich and normalize his or her gut microbiota. Although the method has been known for centuries, interest in it has significantly grown over the last few decades. The two main reasons are the global epidemic of Clostridioides difficile (CDI) infection and an improved knowledge of the GI microbiome and its involvement in various conditions. It seems that FMT may also transfer host phenotyp