Antibiotic
therapy
alone fails to clear the infection in a significant
fraction of patients (∼20–30%), and each round of antibiotic
treatment
for
CDI further increases the risk of recurrence by
approximately
20% [15]. The reason for recurrence of CDI may
be
failure to clear the C. difficile spores with antibiotic treatment,
which
further suppresses the normal microbiota and perpetuates
the underlying problem. Ultimately, a significant fraction of
patients
develop recurrent C. difficile infection syndrome, a condition
characterized by an indefinite series of antibiotic treatments
and
relapses. Analysis of fecal samples in such patients shows
marked
contraction of the normally dominant members of the
Bacteroidetes
and Firmicutes phyla, accompanied by dramatic
expansion
of -Proteobacteria [2,3,16,17]. Infusion of fecal material
taken from a healthy donor promptly leads to establishment of
donor-like
composition of fecal bacteria in the recipient and normalization
of gastrointestinal symptoms. Clinical efficacy of FMT, as
defined
by abrogation of CDI recurrence over 1–2 months following
cessation
of antibiotics, is approximately 90% in multiple case series
of
consecutive patients treated [18]. Furthermore, FMT is confirmed
to
be effective over vancomycin in a randomized, controlled trial
[3].