Lectura accesible en http://www.nature.com/ajg/journal/vaop/ncurrent/full/ajg2012450a.html

1. nature publishing group REVIEWS FROM THE ACG ANNUAL MEETING 1
see related editorial on page x
American Journal of Gastroenterology Lecture: Intestinal
REVIEW
Microbiota and the Role of Fecal Microbiota Transplant
(FMT) in Treatment of C. difficile Infection
Lawrence J. Brandt, MD, MACG1
The vital roles that intestinal flora, now called microbiota, have in maintaining our health are being increasingly
appreciated. Starting with birth, exposure to the outside world begins the life-long intimate association our microbiota
will have with our diet and environment, and initiates determination of the post-natal structural and functional
maturation of the gut. Moreover, vital interactions of the microbiota with our metabolic activities, as well as with the
immunological apparatus that constitutes our major defense system against foreign antigens continues throughout
life. A perturbed intestinal microbiome has been associated with an increasing number of gastrointestinal and
non-gastrointestinal diseases including Clostridium difficile infection (CDI). It has become recognized that fecal
microbiota transplantation (FMT) can correct the dysbiosis that characterizes chronic CDI, and effect a seemingly
safe, relatively inexpensive, and rapidly effective cure in the vast majority of patients so treated. In addition, FMT has
been used to treat an array of other gastrointestinal and non-gastrointestinal disorders, although experience in these
other non-CDI diseases is in its infancy. More work needs to be done with FMT to ensure its safety and optimal route
of administration. There is a conceptual sea change that is developing in our view of bacteria from their role only as
pathogens to that of being critical to health maintenance in a changing world. Future studies are certain to narrow the
spectrum of organisms that need to be given to patients to cure disease. FMT is but the first step in this journey.
Am J Gastroenterol advance online publication, 15 January 2013; doi:10.1038/ajg.2012.450
INTRODUCTION by the National Institutes of Health in 2007 along with related
Although the concept that our intestinal microbiota has an ventures such as the MetaHit (Metagenomics of the Human
important role in maintaining our health is relatively new, the Intestinal tract) consortium, which involves 13 research centers
subject of fecal transplantation has been around for millennia. from 8 countries, are now beginning to be published and will
Its first mention in the literature was during the 4th century, revolutionize knowledge of our microbes and our bodies (2).
when Ge Hong described the use of human fecal suspension by For example, although we knew the human body is inhab-
mouth for food poisoning or severe diarrhea (1). In the 16th ited by a vast number of microorganisms including bacteria,
century, Li Shizhen detailed a variety of fecal preparations called archea (single-celled prokaryotic microorganisms separately
“yellow soup” to be given for diarrhea, abdominal pain, vom- classified from bacteria), viruses, fungi, and even parasites, all
iting, and constipation (1). I will discuss the modern history of which normally live in peaceful coexistence with us, their
of fecal transplantation later, but we can be sure that future hosts, we soon learned that only 5–20% of the intestinal micro-
history will reveal high-quality scientific studies into the nature, biota can be cultured and that culture can reliably distinguish
awesome complexity, and therapeutic powers of our intestinal among bacterial phylogenetic groups, but not down to species-
microbiome. or strain-level (2,3). New approaches to study our microbiota
were developed using culture-independent techniques includ-
The intestinal microbiota ing bacterial 16S ribosomal RNA gene sequencing and DNA
We are witness to a paradigm shift in the way the microbial flora fingerprinting methods, such as terminal restriction fragment
that dwell within our inner recesses are viewed. No longer is it length polymorphisms. A new vocabulary was even developed
simply that the host is “good” and the bacteria that live therein to help detail the “meta” family techniques used to evaluate
“bad”, but the vital roles our intestinal flora, now called micro- the microbiomic functional capacity including metagenomics
biota, have in maintaining health are being increasingly appre- (study of genes collected and sequenced from the environment),
ciated. Results of the Human Microbiome Project launched metabolomics (study of metabolites that are end-products of
1
Montefiore Medical Center, Bronx, New York, USA. Correspondence: Lawrence J. Brandt, MD, MACG, Montefiore Medical Center, 111 East 210th Street, Bronx,
New York 10467, USA. E-mail: lbrandt@montefiore.org
Received 29 August 2012; accepted 6 December 2012
© 2013 by the American College of Gastroenterology The American Journal of GASTROENTEROLOGY

2. 2 Brandt
cellular processes), metaproteomics (study of all proteins in an eign antigens. (Figures 1 and 2). We know that reduced microbial
environment), and metatranscriptomics (study of all RNA mole- stimulation during infancy results in slowed postnatal maturation
cules produced in a population of cells). Microbial communi- of the immune system and delayed development of an optimal
REVIEW
ties differed remarkably at each of the 15 (male) to 18 (female) balance between TH1 and TH2-like immunity (9). During the first
Human Microbiome Project-sampled body sites (nasal pas- year of life, the total number of IgA-, IgG- and IgM-secreting cells
sages, oropharynx, skin, stool, and vagina) and the diversity of is lower in infants born by vaginal delivery than in those born by
each habitat’s signature microbes varied widely among healthy cesarean section, possibly reflecting excessive antigen exposure
individuals, with further variation not just dependent upon across the vulnerable intestine (7).
ethnicity and host genetics, but also on one’s diet and environ- The numbers and types of our intestinal microbiota increase
ment (2). Stool, representing the distal bowel, showed relatively over the first year of life to assume a relatively stable adult pattern
high intra- and inter-subject diversity. The majority of our at the phylum level, but continue to evolve at the species level with
microbiota is anaerobic, and although more than 50 bacterial subsequent dietary and environmental exposures, including anti-
phyla have been described, only four constitute the majority of microbial therapies (3). In one study, diet inventories of 98 indi-
mammalian intestinal microbiota (Bacteroidetes, Firmicutes, viduals were correlated with participants’ fecal enterotypes to show
Actinobacteria, and Proteobacteria) and only two predominate that the Bacteroides enterotype was highly associated with animal
in our intestinal tract: the Bacteroidetes and the Firmicutes; protein, a variety of amino acids, and saturated fats (western diet),
most of the Firmicutes phyla are members of the Clostridia class whereas the Prevotella enterotype was associated with low values
(4). It is estimated that about 4,000 bacterial species reside in for these groups but high values for carbohydrates and simple sug-
our gastrointestinal tract, and that the human microbiota con- ars (agrarian diet). Moreover, microbiome composition changed
tains as many as 1014 bacterial cells, a number that is 10 times within 24 h of dietary alteration (10).
greater than the number of human cells in our body (5). Per Intestinal microbiota has important roles in the post-natal struc-
gram of contents, there is a marked and progressive distal tural and functional maturation of the gut. Germ-free animals
increase in the number of bacteria: 101 in the stomach, 103 in have, for example, enlarged ceca; increased enterochromaffin cell
the duodenum, 104 in the jejunum, 107 in the ileum, and 1012 area; a reduced intestinal surface area with narrower villi resulting
in the colon. This longitudinal heterogeneity of the microbiota from reduced cell regeneration and prolonged cell cycle time, and
population has a predominance of Firmicutes and Proteobac- a smaller villous capillary network; hypotonic and hyporesponsive
teria (notably Helicobacter pylori in the stomach), Firmicutes mesenteric vasculature; impaired lymphoid organs; impaired peri-
and Actinobacteria in the small intestine and a prevalence of stalsis; and abnormal cholesterol and bile acid metabolism (3). It
Bacteroidetes and the Lachnospirae family of Firmicutes in the has been shown, for example, that Bacteroides thetaiotaomicron
colon; of note, bacteria account for 60% of the dry weight of can induce angiogenesis (11); influence enteric nerve function,
feces. The microbiota within the intestinal lumen differs sig- and, therefore, possibly peristalsis (12); and also modulate intes-
nificantly from that dwelling in close proximity to or within tinal glycocalyx structure (13). Various microbiota, including
the intestinal epithelium (6). Therefore, fecal micro-organisms B.thetaiotaomicron and Lactobacilli, are also involved in maintain-
cannot be used as a surrogate for all communities of the bowel ing intestinal barrier integrity through maintenance of cell-to-cell
microflora. Moreover, luminal microbial communities and junctions and promotion of epithelial repair after injury (1).
surface adherent/associated populations are distinct and fulfill The areas in which microbiota have a major influence are legion,
different roles, only some of which I will mention briefly. growing, and far beyond the scope of this general overview. One
Our intestine becomes colonized with micro-organisms during such area is mucosal immunity with influence on immunocytes,
or shortly after birth and the intestinal microbiota of infants deliv- gut-associated lymphoid tissue, Peyer’s patches, IgA-producing
ered by cesarean section differs from that of vaginally-delivered plasma cells, immunoglobulin secretion, and pattern recognition
infants (7,8). The gastrointestinal tract of the newborn is still sterile receptors including toll-like and NOD-like receptors. As a specific
after caesarian section and its microbiota is initiated with feeding; example, the deficiency of CD4 + T-cells in germ-free mice can
in breast-fed infants Bifidobacteria predominate with minor rep- be completely reversed by mono-contamination with Bacteroides
resentation from lactobacilli and streptococci, whereas in formula- fragilis or administration of its polysaccharide capsular antigen (14).
fed infants, similar amounts of Bacteroides and Bifidobacteria are The gastrointestinal tract needs to coexist with the dense car-
found with minor representation from Staphylococci, Escherichia pet of bacteria that overlies its mucosa without inducing exces-
coli, and Clostridia (8). The first colonization of the intestine is a sive immune reaction, and the intestinal microbiota mediates
profound immunological exposure and early maternal inocula- such antigenic tolerance. As examples, intestinal dendritic cells
tion, as occurs with vaginal delivery, likely has an important role in are conditioned to a tolerogenic phenotype by intestinal epithe-
subsequent immune reactions and our susceptibility or resistance lial cells that are stimulated by Lactobacillus spp and certain E.
to certain diseases. Indeed, this initial exposure heralds the con- coli strains (15); B. thetaiotaomicron prevents activation of the
tinuing intimate roles our microbiota will have with our diet and proinflammatory transcription factor NFkβ (16); and Aeromonas
environment, and initiates the vital interactions of the microbiota or Pseudomonas promote intestinal alkaline phosphatase, which
with our metabolic activities, as well as with the immunological dephosphorylates and inactivates the lipopolysaccharide found
apparatus that constitutes our major defense system against for- in the outer membrane of Gram-negative bacteria thus protecting
The American Journal of GASTROENTEROLOGY VOLUME 104 | XXX 2012 www.amjgastro.com

3. Intestinal Microbiota and Fecal Microbiota Transplant for C. difficile 3
Vitamin A
6 SFB
REVIEW
1 Diet 2 Microbiota
3 Unmodified
dietary
components
5 Dietary
components
modified by 4 Microbial
microbiota signals
(acetate) (MAMPs)
?
GPR43
Other Inflammasome TLRs
metabolite ASC
sensors? Pro- MyD88
IL-1β IL-1β
NF-κB
Metabolic signals Classical innate signals
Immunologically Antigen-presenting cell
active nutrients
T cell
and metabolites?
T cell Antigen-presenting cell
mTOR TLRs
Promotes TH1, TH2, TH17 cell Inflammasomes
differentiation; inhibits Treg cell mTOR
differentiation Modulates DC function and
RAR-RXR differentiation
Promotes intestinal T-cell homing;
RAR-RXR and VDR-RXR
promotes TH2 and Treg cell
differentiation AHR
Modulates DC differentiation
VDR-RXR
Promotes Treg cell differentiation; PKR
inhibits TH1 and TH17 cell Regulates inflammatory
differentiation responses
AHR GPR120
Promotes TH17 and Treg cell Inhibits inflammatory responses
differentiation in macrophages
LXR and PPAR
Control T-cell differentination
Figure 1. Inter-relationships of nutrients, immune responses and the microbiome. Ingested nutrients (1) influence our microbiota (2) which, in turn,
changes the nutritional value of the consumed food. (3) Absorbed dietary components interact with a variety of immune cells (e.g., omega 3-fatty acids).
(4) Microbial signals in the form of Microbe Associated Molecular Patterns (MAMPs) also modify local mucosal immune responses through innate
signaling pathways, e.g., the inflammasome or Toll-like receptors (TLRs). (5) Additionally, microbe-modified dietary components (e.g., acetate produced
from fermentation of polysaccharides) provide signals by which the immune system can monitor the metabolic activities of the microbiota. (6) An example
of micronutrients directly modifying intestinal microbial ecology is vitamin A, which can modify the representation of segmented filamentous bacterium
(SFB) in the mouse gut microbiota; SFB induce differentiation of Th17 cells. From Kau et al. (54).
against septic shock (17). Our commensal bacteria, their structural vates defensins. Even the mere presence of microbiota in the gastroin-
components and their metabolic products can induce expression and testinal tract, especially Gram-positive anaerobes, serves as a deterrent
activation of antimicrobial proteins to protect against pathogens and to pathogen colonization; as an example, Lactobacilli and Bifidobacte-
to prevent overgrowth of the commensals themselves (3). For example, ria prevent Listeria infection of cultured epithelial cells (18).
B. thetaiotaomicron colonization of germ-free mice induces As mentioned above, our intestinal microbiota is related to
Paneth cells to express matrilysin, a matrix metalloproteinase that acti- the type of food we eat, but it also is very much involved with
© 2013 by the American College of Gastroenterology The American Journal of GASTROENTEROLOGY

4. 4 Brandt
Bifidobacterium spp.
Clostridium spp.
REVIEW
Bacteroidetes Gm-PG SCFA Conjugation of
SCFAs
B. fragilis (PSA) Gm-LPS metabolism linoleic acid
Cellular immunity Xenobiotics metabolism Oxalate
AMPs IgA Nutrition
Lymphoid organogenesis Drug disposition excretion
Mucosal immunity
Immunocompetence Lap Lipid
Behavior O. fomigenes
Tolerance activation metabolism
NFKB Normalization of
DC tolerization
inactivation HPA stress response
Lactobacillus spp. E. coli B. thetaiotaomicron B. infantis
Peristalsis
Angiogenesis
Glycosylation
Barrier GIT surface maturation
maintenance GIT functional maturation
Figure 2. Some examples of the effects of intestinal microbiota and host physiology. The intestinal microbiota can affect many aspects of normal host
development and function. Members of the microbiota, with their various components or products of metabolism are shown in red. Microbial effects
on the host are shown in green. Affected host phenotypes are shown in blue. AMP, antimicrobial peptides; DC, dendritic cells; Gm, Gram negative;
HPA, hypothalamus-pituitary adrenal; Iap, intestinal alkaline phosphatase; PG, peptidoglycan; PSA, polysaccharide. From Sekirov et al. (3).
appetite regulation, energy utilization, digestion and absorption microbiota transplantation (FMT). Fecal microbiota transplant is
of ingested nutrients, and drug metabolism. Bacterial metabo- the term used when stool is taken from a healthy individual and
lism of dietary fiber to short chain fatty acids, and conversion of instilled into a sick person to cure a certain disease. As the exact
indigestible polysaccharides to absorbable monosaccharides are agent or agents that effect cure is currently unknown, the term
well known examples of such interaction. B. thetaiotaomicron, as fecal microbiota transplant (FMT) presently is preferred to fecal
another example, has been shown to upregulate expression of pan- bacterial transplantation, or fecal bacteriotherapy; stool trans-
creatic co-lipase and an intestinal Na + /glucose co-transporter (12). plant is an accurate but unaesthetic term (21).
Awareness of the interplay between these complex metabolic func- I’ve already reviewed the very early history of FMT, but FMT
tions and the intestinal microbiome sets the stage to study whether also has been used for centuries in veterinary medicine per rectum
manipulation of the microbiome can be used to understand and to treat horses with diarrhea or per os as rumen transfaunation to
treat conditions of obesity and underweight (19). Inter-individual treat a variety of illness in cattle. Its first clinical use in the English
and inter-population differences in intestinal microbiomes with language dates back to a 1958 case series of four patients with
their attendant varied metabolic profiles may explain the differ- pseudomembranous enterocolitis, three of whom were critically
ent toxicities of commonly used therapeutics in varied geographic/ ill. C. difficile had not yet been recognized as a cause of pseu-
cultural populations and set the stage for the development of domembranous colitis and Micrococcus pyogenes (hemolytic,
personalized medicine-based on one’s intestinal microbiome coagulase-positive Staphylococcus aureus) was cultured from each
profile (20). patient’s stool. Fecal enemas were administered as an adjunct to
antibiotic treatment and all four patients had “dramatic” reso-
Clostridium difficile infection and fecal microbiota lution of symptoms within 24–48 h of FMT (22); the first use
transplantation (FMT): introduction of FMT for confirmed recurrent CDI was reported in 1983 by
A perturbed intestinal microbiome has been associated with an Schwan et al. (23), in a 65-year-old woman who thereafter had
increasing number of gastrointestinal and non-gastrointestinal “prompt and complete normalization of bowel function”. Up until
diseases which brings us to C. difficile infection (CDI) and fecal 1989, retention enemas had been the most common technique
The American Journal of GASTROENTEROLOGY VOLUME 104 | XXX 2012 www.amjgastro.com

5. Intestinal Microbiota and Fecal Microbiota Transplant for C. difficile 5
for FMT, however, alternative methods of fecal infusion subse- C. difficile excretion and that upon cessation of treatment relapse
quently were developed including nasogastric duodenal tube in occurred, just as in the human who has recurrent CDI. FMT
1991 (24), colonoscopy in 2000 (25), and self-administered ene- using homogenized feces from a healthy mouse and given by
REVIEW
mas in 2010 (26). In 2011, a review was reported of 325 cases of oral gavage, suppressed C. difficile shedding for months. Finally,
FMT performed worldwide, ~75% of which had been adminis- these authors reasoned that introduction of a phylogenetically
tered by colonoscopy or retention enema, and 25% by nasogastric diverse but limited bacterial mixture might trigger recovery of
or nasoduodenal tube, or by EGD (27,28). Worldwide mean cure the intestinal ecosystem and disrupt the stability of the micro-
rates to date are consistently around 91% (28) and FMT is effec- biota of the mice with chronic CDI. Ultimately they fashioned
tive even in patients with the C. difficile NAP1/BI/027 strain (29). a mixture of six physiologically diverse species including both
Route does seem to influence results, however, and when FMT obligate and facultative anaerobes that resolved the CDI. This
is done via upper tract endoscopy, nasogastric, or nasoduodenal series of experiments addresses the major concepts involved in
tube, resolution rates are in the range of 76–79% (28,30). Regard- trying to understand the pathophysiology of the effectiveness of
less of route, FMT appears to be safe, with no adverse effects or FMT in treating patients afflicted with chronic, recurrent CDI.
complications directly attributed to the procedure yet published (Figure 3): (1) perturbation of the intestinal microbiota, (2)
(21,31). colonization and establishment of C. difficile, which allows (3)
persistence of a disturbed intestinal microbiota with (4) altered
CDI and FMT: pathophysiology and rationale intestinal fermentation, and (5) loss of nutrients to the bowel; (6)
The rationale for FMT in patients with recurrent CDI lies in FMT induces re-establishment of microbiota diversity and (7)
the belief that CDI results when the community of organisms termination or suppression of C. difficile colonization. It is likely
residing in the gastrointestinal tract is perturbed and that per- that the colitis seen with chronic CDI is also associated with
sisting imbalance, or dysbiosis, explains the high CDI recur- increased colonic permeability that is worsened by the reduc-
rence rates of 10–20% after initial antibiotic therapy and up to tion in butyrate and acetate and which then facilitates colonic
40–65% in patients who are retreated for a second episode (32). protein loss with hypoalbuminemia, and bacterial translocation
It is believed that reintroduction of normal flora via donor feces with sepsis, especially in cases of severe CDI.
corrects the imbalance, restores both phylogenetic richness and
colonization resistance, and thereby enables recovery of normal CDI and FMT: how to do it
bowel function; this contrasts with the chronic use of antibiotics, The potential for transmission of infectious agents is a major
which, in a sense, perpetuates the very condition that lead to the concern, however, and rigorous screening tests are recom-
initial episode of CDI, namely an altered intestinal microbiome. mended to reduce such risk (21). As an integral part of our pro-
In an elegant series of experiments, Lawley et al. (33) treated tocol for a double-blind randomized controlled trial of FMT for
mice with clindamycin for 7 days and then infected them with recurrent CDI (see below), the NIH required that donor stool be
C. difficile (genotype 027/BI) isolated from hospitalized patients. tested for C. difficile toxin, enteric bacterial pathogens (includ-
They showed that the mice went on to develop highly conta- ing specifically Listeria monocytogenes, Vibrio cholera and Vibrio
gious, chronic disease with persistent dysbiosis characterized by: parahemolyticus), parasites such as Giardia (Giardia antigen test)
(1) a simplified microbiota with reduced phylotypic diversity; Cryptosporidium (Cryptosporidium antigen test), and Isospora
(2) opportunistic pathogens (e.g., Klebsiella pneumonia, E. coli, (acid-fast stain), and Rotavirus; donor blood must be screened
Proteus mirabilis, Parabacteroides distasonis, and Enterococcus for hepatitis A (IgM), B (HBsAg, anti-HBc (IgG and IgM), and
faecalis— all of which have been identified in the microbiota of anti-HBsAg) and C (HCV antibody) viruses, human immunode-
humans with chronic CDI (34); (3) upregulated pro-inflamma- ficiency virus (HIV) types 1 and 2, and syphilis. Screening for H.
tory genes—particularly those known to promote neutrophil pylori is also prudent regardless whether FMT is performed via
infiltration; (4) and altered metabolite production, similar the upper or lower route. Recipients are tested for HIV 1 and 2,
to that which occurs in the human immune response to CDI. Hepatitis A, C, and syphilis. This testing is much more rigorous
Specifically, they demonstrated a disturbance in fecal short- chain and extensive than that performed in the community, where most
fatty acids, which are the end-products of intestinal bacterial practitioners just have donor stool screened for enteric patho-
metabolism of ingested complex carbohydrates. This disturbance gens, ova and parasites, and C. difficile toxin. Of course, because
included a reduction in butyrate and acetate, which are the main of the ready availability of stool, patients may accept offers of
nutrient sources for the colon and an increase in succinate levels; unscreened stool from well-meaning friends and relatives who
of note, there was an increase in P. disasonis, which is a succinate are aware of FMT. I have had several patients who wanted me to
producer. Acetate and butyrate influence a wealth of functions perform FMT on them after self-administration of unscreened
in the colon; acetate: crypt cell proliferation, motility, blood donor stool had failed. This practice of using unscreened stool
flow, adipogenesis, and cellular immunity; butyrate: colonocyte is to be eschewed, except perhaps for emergent FMT, when tim-
health, inflammation, intestinal permeability, inflammation, ing may be more critical than long-term safety outcome. As the
apoptosis, cell growth and differentiation, and barrier function, perturbing effect of antibiotics on the intestinal microflora can
to name but a few (35). Lawley et al. (33) then demonstrated that persist for 3 months or more, donors are excluded if they have
vancomycin administration was associated with suppression of had antibiotics within this time; high-risk sexual behaviors, a
© 2013 by the American College of Gastroenterology The American Journal of GASTROENTEROLOGY

6. 6 Brandt
(a) Homeostasis
REVIEW
(d) Expansion of commensals (b) Antibiotic perturbation
(c) Transient dysbiosis
(h) C.difficile clearance (e) C.difficile exposure
(g) Disrupting dysbiosis (f) Persistent dysbiosis
Bacteriotherapy
or FMT
Figure 3. Role of antibiotics and C. difficile in perturbing Intestinal homeostasis and the corrective effect of fecal microbiota transplantation (FMT).
Intestinal homeostasis (a) is characterized by a diverse, stable microbiota. Antibiotic perturbation (b–c) kills susceptible bacteria resulting in a less diverse
community structure with loss of colonization resistance. In the absence of opportunistic infection, the microbiota usually recovers its diversity (d) to
re-establish homeostasis and colonization resistance (a). Exposure to C. difficile (e) after antibiotic perturbation (b), however, can lead to persistent
dysbiosis (f). Bacteriotherapy or FMT can disrupt the dysbiosis (g) allowing clearance of C. difficile (h) and re-establishment of intestinal homeostasis (a).
Modified from Lawley et al. (33).
body piercing or tattoo in the previous 3 months or recent incar- blender is to be used for several patients, its parts would have to
ceration are also exclusions. A history of diarrhea, constipation, be sterilized before the next procedure. Some authors use milk
inflammatory bowel disease, colorectal polyps or cancer, irri- as the suspending fluid, others water; saline and milk may give
table bowel syndrome, immunocompromise, morbid obesity, slightly lower resolution (86.2 and 88.6%, respectively) and recur-
metabolic syndrome, atopy, and chronic fatigue syndrome are rence (3.0 and 3.2%, respectively) rates, while water may give
additional donor exclusions because they conceivably may be higher resolution (98.5%) and recurrence (7.8%) rates (28). The
transmittable by inoculation with intestinal microbiota. amount of stool to use has not been standardized, although those
One systematic review provided data to suggest that FMT given to weighing and measuring rather than just “eyeballing” the
using stool from a related donor (spouse, or intimate partner), product’s appearance favor 50 g in 250 cc of diluent. It seems as
yields a somewhat higher rate (93.3%) of CDI resolution than if more is better and most “FMTers” are now using about 300 cc
when stool from an unrelated donor (84%) was used (28). More for colonic FMT and 60 cc for upper tract FMT. An administered
recent experience with frozen/thawed or fresh fecal preparations volume of < 200 ml gave a resolution rate of 80% and a relapse
obtained from “standard” or “universal” donors, however, gave rate of 6.2%, whereas a volume of > 500 ml gave a resolution rate
excellent results (90–92% resolution, 9% recurrence) exceeding of 97.3% and a relapse rate of 4.7%. Use of < 50 g of stool was
those obtained with patient-selected donors (70% resolution, associated with resolution and relapse rates of 8.2% and 3.8%,
30% recurrence), and casting doubt on preference for related or respectively, whereas > 50 g of stool had resolution and relapse
intimate contacts (36). rates of 86.2% and 1.0%, respectively (28). I like to use donor stool
So what are the “nuts and bolts” of FMT? The donor has a rela- within 8 h of passage although this time limit has never been stud-
tively simple job: to provide the stool in a timely fashion. This, I ied rigorously. Stool should not be frozen and need not, but may,
have seen, may cause a level of “performance anxiety” in some be refrigerated for travel. After adding my beverage of choice to
donors. To facilitate passage and to enable me to work with a the stool and getting it to the proper consistency, I filter the mix-
soft stool, I have the donor take a double dose of milk of mag- ture through gauze pads to remove large particulate matter that
nesia before bedtime the night before the procedure. A soft stool may obstruct the colonoscope’s channel and then draw the elixir
is passed into a clean plastic container. I add non-bacteriostatic into 60 cc catheter-tipped syringes. It is recommended that stool
saline to the stool, stir it, shake it, and mix it thoroughly. Oth- preparation be performed under a hood, because stool is rated as
ers have opted for the blender method and some practitioners a Level 2 biohazard, although this recommendation is not practi-
have even had patients bring their own blender. Obviously, if a cal and this is the safest stool we, as gastroenterologists, will ever
The American Journal of GASTROENTEROLOGY VOLUME 104 | XXX 2012 www.amjgastro.com

7. Intestinal Microbiota and Fecal Microbiota Transplant for C. difficile 7
encounter. Recipients should take a large volume colon lavage study, principal investigators of which are Dr Colleen Kelly
before the procedure, regardless of which route is chosen. In cases and I, will evaluate FMT in 80 patients with at least three bouts
of recurrent CDI, I have the patients stop their vancomycin and of CDI, and compare results of blinded FMT, using either donor
REVIEW
other antibiotics 3 days before the procedure if possible; this too or recipient stool for the transplant.
has not been studied against continuing the antibiotics up until or The use of stool for such transplants is but the first step in a
even after the procedure. I also have the recipient take two lopera- long journey. Stool is the ultimate probiotic but greater knowl-
mide tablets before they leave home or about an hour before the edge of the intestinal microbiota and its functions will certainly
procedure to help them hold the administered stool for at least enable us to administer one or more intestinal micro-organisms
4 h, and preferably 6 h, after FMT. To actually do the transplant,
I perform a colonoscopy and upon reaching the cecum, I remove
the accessory channel cap of the colonoscope, connect a piece of
suction tubing to it, and then administer one syringe-full of stool Table 1. Disorders associated with an altered intestinal
suspension after another into the cecum/ascending colon or into microbiome
the ileum until the desired amount has been given. I have on many Gastrointestinal
occasions taken random colon biopsy specimens during insertion Cholelithiasis
to ascertain histology without adverse effect. After infusion of the
Colorectal cancer
donor stool, I withdraw swiftly, aspirating air only from the distal
left colon, sigmoid and rectum for patient comfort. Hepatic encephalopathy
Idiopathic constipationa
CDI and FMT: long-term follow-up and safety issues IBSa
In the only long-term follow-up of FMT to date, a five-
IBDa
medical center cross-country joint effort, 77 patients who had
Familial Mediterranean Fever
had FMT and were followed for more than 3 months experi-
enced a 91% primary cure rate and a 98% secondary cure rate, Gastric carcinoma and lymphoma
the latter defined as cure enabled by use of antibiotics to which Recurrent Clostridium difficile infectiona
the patient hadn’t responded to before the FMT or by a second Non-gastrointestinal
FMT (37). It is interesting that 97% of these patients stated they
Arthritis
would have another FMT were they to develop CDI again and
58% said they would choose to have FMT rather than antibiotics. Asthma
It is not unusual for patients to develop some gastrointestinal Atopy
complaints or altered bowel habit for several days after FMT, Autisma
including absence of bowel movement, abdominal cramping,
Autoimmune disorders
gurgling bowel sounds, or increased feelings of gaseousness.
Chronic fatigue syndromea
Of the 77 subjects in this study, four developed an autoimmune
disease (rheumatoid arthritis, Sjogren syndrome, idiopathic Diabetes mellitus and insulin resistancea
thrombocytopenic purpura, and peripheral neuropathy) at some Eczema
time after the FMT, although a clear relationship between the Fatty liver
new disease and FMT was not evident. Safety of FMT in immu-
Fibromyalgiaa
nosuppressed patients needs to be established, although limited
experience to date would suggest immune-compromise is not Hay fever
of concern. I personally have performed FMT in many patients Hypercholesterolemia
who were either on glucocorticoids, immunosuppressive Idiopathic thrombocytopenic purpuraa
(6-mercaptopurine, azathioprine), or biological agents (inflixi-
Ischemic heart disease
mab, adalimumab), or who had diseases or therapies charac-
Metabolic syndromea
terized by immunocompromise (kidney transplant, chronic
lymphocytic leukemia, lymphoma, primary immune deficiency, Mood disorders
Schwachman–Diamond syndrome) without ill effect. Nonethe- Multiple sclerosisa
less, safety remains the prime consideration and larger numbers Myoclonus dystoniaa
of observations in controlled circumstances are needed. Con-
Obesity
trolled trials also are necessary to prove the efficacy of FMT,
and to determine the optimal route of administration among Oxalic acid kidney stones
other variables. Two such randomized, controlled trials are Parkinson’s diseasea
pending; one that compares conventional vancomycin therapy IBD, inflammatory bowel disease; IBS, irritable bowel syndrome.
alone and with bowel lavage, or with bowel lavage plus FMT a
Indicates some reports on transient or long-term improvement or cure with
fecal microbiota transplant.
is currently in progress (38). A recently approved NIH-funded
© 2013 by the American College of Gastroenterology The American Journal of GASTROENTEROLOGY

8. 8 Brandt
or genetically refined products derived from stool rather children; and autistic symptoms have sometimes been reduced by
than stool itself to treat CDI. The next step in this journey oral vancomycin treatment (3). Although at first glance it appears
has already been taken with the development of a standard- as if there is no connection with neuropsychiatric disease and
REVIEW
ized filtered, frozen preparation of stool for FMT and use of a intestinal flora, studies now have expanded the original concept
“universal donor” (36). of the brain-gut axis and recognize the brain-gut-microbiota axis
(51). Moreover, the increasing recognition of the role that micro-
When should FMT be done? biota have in affecting mood and thought is actively being worked
When should FMT be done for CDI? The clearest indication, on (52,53).
as discussed above, is recurrent or refractory disease, but even
this is not universally accepted and awaits the results of rand-
omized controlled trials; to quote a reviewer of our NIH grant, CONCLUSION
however, “…we all know it works”. I believe it also has a role as I believe that the intestinal microbiota will be shown to have
first-line treatment for patients with CDI rather than antibiot- important roles in maintaining our health and modulating energy
ics because of its rapid effect, minimal risk, relatively low cost expenditure, inflammation, and resistance or susceptibility to var-
and reestablishment of a “balanced” colonic microbiota (39). I, ious disease, some gastrointestinal and some not. Bacteria should
and others, also have used FMT to treat patients with severe CDI no longer be regarded as just “bad” guys and we have come a long
manifest by toxic megacolon or ileus and have seen the patient’s, way since Hippocrates said,” All disease begins in the gut”; today
family’s, gastroenterologist’s, and even surgeon’s relief as the he might instead say “Our health is determined by the micro-
patient’s abdominal distention, fever, and white blood cell count biota in our gut”. We are witnessing a paradigm shift in the way
decreased, occasionally within hours of the procedure; in none we understand health and treat disease and in its center is our
of these cases was the patient’s condition or course of disease microbiota.
worsened by FMT.
FMT also has been used to treat a variety of other gastro- CONFLICT OF INTEREST
intestinal disorders including ulcerative colitis, Crohn’s disease, Guarantor of the article: Lawrence J. Brandt, MD, MACG.
irritable bowel syndrome, and constipation and there is a grow- Financial support: None.
ing literature on an altered intestinal microbiome in these disor- Potential competing interests: Dr Brandt is on the ‘Speaker’s
ders (40–42) (See Table 1). I now have personal experience with Bureau of Optimer Pharmaceuticals, Inc. and has received a research
FMT in 20 patients with UC, 4 with Crohn’s disease and 20 with grant from Optimer Pharmaceuticals, Inc.
IBS; and in all groups, I have noted remarkable symptomatic
improvement in some individuals. Rigorous studies of FMT in REFERENCES
these areas are also needed to determine who is the optimal candi- 1. Zhang F, Luo W, Shi Y et al. Should we standardize the 1700-year-old
date, and via what route and how often FMT should be delivered, fecal microbiota transplantation? Am J Gastroenterol 2012; 107:1755.
2. The Human Microbiome Project Consortium.. Structure, function and
among other considerations. diversity of the healthy human microbiome. Nature 2012;486:207–14.
Use of FMT is not confined to gastrointestinal disease and there 3. Sekirov I, Russell SL, Antunes CM, Finlay RB. Gut microbiota in health and
is a scattering of studies on the intestinal microbiota or FMT in a disease. Physiol Rev 2010;90:859–904.
4. Eckburg PB, Bik EM, Bernstein CN et al. Diversity of the human intestinal
wide range of disorders (see Table 1) including Parkinson’s dis- microbial flora. Science 2005;308:1635–8.
ease (43), fibromyalgia, chronic fatigue syndrome (44), multiple 5. Ley RE, Peterson DA, Gordon JI. Ecological and evolutionary forces
sclerosis (45), myoclonus dystonia (46), obesity (47) insulin resist- shaping microbial diversity in the human intestine. Cell 2006;124:837–48.
6. Swidsinski A, Loening-Bauke V, Lochs H, Hale LP. Spatial organization
ance and the metabolic syndrome (48), and childhood regres- of bacterial flora in normal and inflamed intestine: a fluorescence in situ
sive autism (49) among others. The beneficial effect of FMT on hybridization study in mice. World J Gastroenterol 2005;11:1131–40.
non-gastrointestinal disorders was an unanticipated observation 7. Huurre A, Kalliomaki M, Rautava S et al. Mode of delivery: effects on gut
microbiota and humoral immunity. Neonatology 2008;93:236–40.
that was initially made in one patient with UC and idiopathic 8. Harmsen HJ, Wildeboer-Veloo AC, Raangs GC et al. Analysis of
thrombocytopenic purpura who had remission of both diseases intestinal flora development in breast-fed and formula-fed infants by using
(50) and in three patients with multiple sclerosis who underwent molecular identification and detection methods. J Pediatr Gastroenterol
Nutr. 2000;30:61–7.
FMT for chronic constipation, in whom normal defecation was 9. Biasucci G, Rubini M, Riboni S et al. Mode of delivery affects the bacterial
achieved and improvement was noted in motor symptoms and community in the newborn gut. Early Hum Dev 2010;86 (Suppl 1): 13–5.
urinary function resulting in a regained ability to walk and removal 10. Wu GD, Chen J, Hoffmann C et al. Linking long-term dietary patterns with
gut microbial enterotypes. Science 2011;334:105–8.
of indwelling catheters (45). Of 34 patients with chronic fatigue 11. Stappenback TS, Hooper LV, Gordon JI. Developmental regulation of
syndrome who were reachable 11–28 months after FMT, 14 (41%) intestinal angiogenesis by indigenous microbes via Paneth cells. Proc Natl
reported persistent relief and 12 (35%) showed little or late relief Acad Sci USA 2002;99:15451–5.
12. Hooper LV, Wong MH, Thelin A et al. Molecular analysis of commensal
of their chronic fatigue symptoms (44). In autism, the link with host-microbial relationships in the intestine. Science 2001;291:881–4.
intestinal microbiota is supported by observations that disease 13. Hooper LV, Gordon JI. Commensal host-bacterial relationships in the gut.
onset often follows antimicrobial therapy; associated gastrointesti- Science 2001;292:1115–8.
14. Mazmanian SK, Lin CH, Tzianabos AO, Kasper DL. An immunomodula-
nal abnormalities are not uncommon; certain Clostridium spp. are tory molecule of symbiotic bacteria directs maturation of the host immune
present at 10-fold higher numbers in stool samples from autistic system. Cell 2005;122:107–18.
The American Journal of GASTROENTEROLOGY VOLUME 104 | XXX 2012 www.amjgastro.com

9. Intestinal Microbiota and Fecal Microbiota Transplant for C. difficile 9
15. Zeuthen LH, Fink LN, Frokiner H. Epithelial cells prime the immune 34. Chang JY, Antonopoulos DA, Kalra A et al. Decreased diversity of the fecal
response to an array of gut-derived commensals towards a tolerogenic microbiome in recurrent Clostridium difficile-associated diarrhea. J Infect
phenotype through distinct actions of thymic stromal lymphopoietin and Dis 2008;197:435–8.
transforming growth-factor beta. Immunology 2008;123:197–208. 35. Macfarlane GT, Macfarlane S. Fermentation in the human large intestine.
REVIEW
16. Kelly D, Campbell JI, King TP et al. Commensal anaerobic gut bacteria Its physiologic consequences and the potential contribution of probiotics.
attenuate inflammation by regulating nuclear-cytoplasmic shuttling of J Clin Gastrooenterol 2011;45:S120–7.
PPAR-gamma and RelA. Nat Immunol 2004;5:104–12. 36. Hamilton MJ, Weingarden AR, Sadowsky MJ et al. Standardized frozen
17. Bates JM, Akerland J, Mittge E, Guillemin K. Intestinal alkaline phosphatase preparation for transplantation of fecal microbiota for recurrent
detoxifies lipopolysaccharide and prevents inflammation in zebrafish in Clostridium difficile infection. Am J Gastroenterol 2012;107:761–7.
response to the gut microbiota. Cell Host Microbe 2007;2:371–82. 37. Brandt LJ, Aroniadis OC, Mellow M et al. Long-term follow-up of colono-
18. Corr SC, Gahan CG, Hill C. Impact of selected Lactobacillus and Bifido- scopic fecal microbiota transplant for recurrent Clostridium difficile
bacterium species on Listeria monocytogenes infection and the mucosal infection. Am J Gastroenterol. 2012;107:1079–87.
immune response. FEMS Immunol Med Microbiol 2007;50:380–8. 38. van Nood E, Speelman P, Kuiper EJ et al. Struggling with recurrent Clostridium
19. Flint HJ. Obesity and the gut microbiota. J Clin Gastroenterol difficile infections: is donor faeces the solution? Euro Surveill 2009;14:pii:19316.
2011;45:S128–32. 39. Brandt LJ, Borody TJ, Campbell J. Endoscopic Fecal Microbiota Transplan-
20. Nicholson JK, Holmes E, Wilson ID. Gut microorganisms, mammalian tation: “First-Line” treatment for severe Clostridium difficile infection.
metabolism, and personalized health care. Nat Rev Microbiol 2005;3:431–8. J Clin Gastroenterol. 2011;45:655–7.
21. Bakken JS, Borody T, Brandt LJ et al. Fecal Microbiota Transplanta- 40. Sartour RB. Microbial influences in inflammatory bowel diseases.
tion (FMT) Workgroup. Treating Clostridium difficile infection with Gastroenterology 2008;134:577–94.
fecal microbiota transplantation. Clin Gastroenterol and Hepatol 41. Rajiilic-Stojanovic M, Biagi E, Heilig HG et al. Global and deep molecular
2011;9:1044–9. analysis of microbiota signatures in fecal samples from patients with
22. Eiseman B, Silen W, Bascom GS et al. Fecal enema as an adjunct in the irritable bowel syndrome. Gastroenterology 2011;141:1792–801.
treatment of pseudomembranous enterocolitis. Surgery 1958;44:854–9. 42. Quigley E. The enteric microbiota in the pathogenesis and management of
23. Schwan A, Sjolin S, Trottestam U et al. Relapsing Clostridium difficile constipation. Best Pract Res Clin Gastroenterol 2011;25:119–26.
enterocolitis cured by rectal infusion of homologous faeces. Lancet 43. Anathaswamy A. Faecal transplant eases symptoms of Parkinson’s.
1983;2:845. New Scientist; issue 2796, 19 January 2011.
24. Aas J, Gessert CE, Bakken JS. Recurrent Clostridium difficile colitis: case 44. Borody TJ, Nowak A, Torres M et al. Bacteriotherapy in chronic fatigue
series involving 18 patients treated with donor stool administered via a syndrome: a retrospective review. Am J Gastroenterol 2012;107 (Suppl 1),
nasogastric tube. Clin Infect Dis 2003;36:580–5. S591–592 (A1481).
25. Persky SE, Brandt LJ. Treatment of recurrent Clostridium difficile-associated 45. Borody TJ, Leis S, Campbell J et al. Fecal microbiota transplantation (FMT)
diarrhea by administration of donated stool directly through a colonoscope. in multiple sclerosis (MS) [abstract]. Am J Gastroenterol 2011;106:S352.
Am J Gastroenterol 2000;95:3283–5. 46. Borody TJ, Rosen DM, Torres M et al. Myoclonus-dystonia (M-D)
26. Silverman MS, Davis I, Pillai DR. Success of self-administered home fecal mediated by GI microbiota diarrhoea treatment improves M-D symptoms.
transplantation for chronic Clostridium difficile infection. Clin Gastro- Am J Gastroenterol 2011;106:S352.
enterol Hepatol 2010;8:471–3. 47. Turnbaugh PJ, Ley RE, Mahowald MA et al. An obesity-associated
27. Brandt LJ, Reddy S. Fecal microbiota transplantation for recurrent gut microbiome with increased capacity for energy harvest. Nature
Clostridium difficile infection. J Clin Gastroenterol 2011;45:S159–67. 2006;444:1027–31.
28. Gough E, Shaikh H, Manges AR. Systematic review of intestinal microbiota 48. Vrieze A, van Nood E, Holleman F et al. Transfer of intestinal microbiota
transplantation (fecal bacteriotherapy) for recurrent Clostridium difficile from lean donors increases insulin sensitivity in subjects with metabolic
infection. Clin Infect Dis 2011;53:994–1002. syndrome. Gastroenterology 2012;143:913–6.
29. Mattila E, Uusitalo-Seppälä R, Wuorela M et al. Fecal Transplantation, 49. Finegold SM, Molitors D, Song Y. Gastrointestinal micro flora studies in
through colonoscopy, is effective therapy for recurrent Clostridium difficile late-onset autism. Clin Infect Dis. 2002;35:S6–16.
infection. Gastroenterology 2010;142:490–6. 50. Borody TJ, Campbell J, Torres M et al. Reversal of idiopathic thrombo-
30. Rubin TA, Gessert CE, Aas J, Bakken JS. Fecal microbiome transplanta- cytopenic purpura (ITP) with fecal microbiota transplantation (FMT)
tion for recurrent Clostridium difficile infection: report on a case series. [abstract]. Am J Gastroenterol 2011;106:S352.
Anaerobe; 23 November 2012 pii S1075–9964(12)00153-9; doi: 10.1016/ 51. Collins SM, Bercik P. The Relationship between intestinal microbiota and
j.anaerobe.2012.11.004 (e-pub ahead of print). the central nervous system in normal gastrointestinal function and disease.
31. Borody TJ, Warren EF, Leis SM et al. Bacteriotherapy using fecal flora: toy- Gastroenterology 2009;136:2003–14.
ing with human motions. J Clin Gastroenterol 2004;38:475–83. 52. Bravo JA, Forsythe P, Chew MV et al. Ingestion of Lactobacillus strain
32. McFarland LV, Surawicz CM, Rubin M et al. Recurrent Clostridium difficile regulates emotional behavior and central GABA receptor expression in
Disease. Epidemiology and Clinical Characteristics. Infect Contr and Hosp a mouse via the vagus nerve. Proc Natl Acad Sci USA 2011;108:16050–5.
Epidemiol 1999;20:43–50. 53. Bercik P, Park AJ, Sinclair D et al. The anxiolytic effect of Bifidobacterium
33. Lawley TD, Clare S, Walker AW et al. Targeted restoration of the intestinal longum NCC3001 involves vagal pathways for gut-brain communication.
microbiota with a simple, defined bacteriotherapy resolves relapsing Neurogastroenterol Motil 2011;23:1132–9.
Clostridium difficile disease in mice. PLoS Pathog 8: e1002995; 54. Kau AL, Ahern PP, Griffen NW et al. Human nutrition, the gut microbiome,
doi: 10.1371/journal.ppat.1002995. and immune system: envisioning the future. Nature 2011;474:327–36.
© 2013 by the American College of Gastroenterology The American Journal of GASTROENTEROLOGY