What is Fecal Microbiota Transplantation (FMT)?

The Intestinal Microbiome

The intestinal microbiome is made up of many different microorganisms, including bacteria, viruses, and yeast. Bacteria make up the majority of the microbiome and there is a significant amount of diversity among bacterial species. The specific distribution of bacterial species will normally change over the course of a dog’s life, with significant differences between neonates, infants, and adults.

In healthy adult dogs, the bacterial population of the microbiome is divided amongst Firmicutes, Bacteroides, Proteobacteria, and Actinobacteria. The bacterial population can be affected by diet, the local immune system of the GI tract, intestinal parasites, and systemic illness. There appears to be strong evidence to link gastrointestinal disease with decreased diversity of the microbiome, but it is less clear which comes first: does gastrointestinal disease change the microbiome, or does a change in the microbiome cause gastrointestinal disease?

What is Fecal Microbiota Transplantation (FMT)?

Fecal Microbiota Transplantation (FMT) is an emerging therapeutic approach for treatment of inflammatory and infectious intestinal diseases (enteropathies) in dogs. Conditions treated with FMT have included parvoviral enteritis, granulomatous colitis, clostridiosis, and chronic enteropathy.

The overall goal of FMT is to restore a balanced and functional intestinal microbiome by transplanting fecal material from a healthy donor. Donor screening is critical, and in general donors should be free from infectious disease, parasites, and antibiotic use for at least several months.

Performing FMT

There are multiple ways to perform FMT, but the first step is to prepare the donor sample by mixing it in water until it is a smooth and liquid consistency.

The most common way to perform FMT is to administer an enema of the fecal sample. The benefit of the enema technique is that is can be performed with the dog completely awake or with light sedation, and does not require a lot of time or specialized equipment. The main downside is that the sample can more easily leak out before the bacteria have a chance to colonize the colon.

Another way to perform FMT is to deliver the fecal sample through colonoscopy. This requires general anesthesia and an endoscope, but can help ensure delivery of the sample further along the colon to decrease the likelihood of premature sample loss.

Regardless of the technique used it is not uncommon to require multiple treatments, especially in dogs with more chronic GI signs. A positive response means an improvement in GI signs and potentially the ability to de-escalate other therapies.