Fecal microbiota transplant (FMT) has emerged as a highly efficacious treatment 
for difficult cases of refractory and/or recurrent Clostridium difficile 
infection (CDI). There have been many well-conducted randomized controlled 
trials and thousands of patients reported in case series that describe success 
rates of approximately 90% following one or more FMT. Although the exact 
mechanisms of FMT have yet to be fully elucidated, replacement or restoration of 
a 'normal' microbiota (or at least a microbiota resembling those who have never 
had CDI) appears to have a positive effect on the gut dysbiosis that is thought 
to exist in these patients. Furthermore, despite being aesthetically 
unappealing, this 'ultimate probiotic' is a particularly attractive solution to 
a difficult problem that avoids repeated courses of antibiotics. The lack of 
clarity about the exact mechanism of action and the 'active ingredient' of FMT 
(e.g., individual or communities of bacteria, bacteriophage, or bioactive 
molecules such as bile acids) has hindered the ability to produce a standardized 
and well-characterized FMT product. There is no standard method to produce 
material for FMT, and there are a multitude of factors that can vary between 
institutions that offer this therapy. Only a few studies have directly compared 
clinical efficacy in groups of patients who have been treated with FMT prepared 
differently (e.g., fresh vs. frozen) or administered by different route (e.g., 
by nasojejunal tube, colonoscopy or by oral administration of encapsulated 
product). More of these studies should be undertaken to clarify the superiority 
or otherwise of these variables. This review describes the methods and protocols 
that two English NHS hospitals independently adopted over the same time period 
to provide FMT for patients with recurrent CDI. There are several fundamental 
differences in the methods used, including selection and testing of donors, 
procedures for preparation and storage of material, and route of administration. 
These methods are described in detail in this review highlighting differing 
practice. Despite these significant methodological variations, clinical outcomes 
in terms of cure rate appear to be remarkably similar for both FMT providers. 
Although both hospitals have treated only modest numbers of patients, these 
findings suggest that many of the described differences may not be critical 
factors in influencing the success of the procedure. As FMT is increasingly 
being proposed for a number of conditions other than CDI, harmonization of 
methods and techniques may be more critical to the success of FMT, and thus it 
will be important to standardize these as far as practically possible.