Although
typically the topmost concern for providers, patients,
and
regulators, the infectious disease risk associated with FMT thus
far
appears to be extremely small. Of course, this risk will not
be
fully known in absence of large scale clinical trials or mandated
registries and long-term follow-up of all FMT recipients.
Nevertheless,
as FMT is an increasingly common clinical procedure
with thousands of patients being treated across the globe,
the
paucity of infectious complication reports that are even only
possibly
associated with FMT is almost surprising [46]. This is especially
so given that the majority of recipients are elderly patients
with
multiple systemic problems and a significant fraction are
patients
with
IBD,
with disrupted mucosal gut barrier, intrinsically
defective mucosal immunity, and concurrent treatment with
immunosuppressive
medications.
Therefore, it is very likely that
the
commensal microbiota and vigorous mucosal immune systems
of
clinically
healthy individuals are very successful at containing
potential
enteric pathogens in the donor material. An additional
safety
mechanism
may be the limits imposed by transplant itself,
which
allows only one donor and a single donation to contribute to
an
individual dose of transplant material. This ensures that the risk
posed
by a single donor is always limited. For these reasons, the
infectious
disease safety advantages of synthetic microbiota may
be
minimal at best. In fact, it is worthy of note that bioreactors do
not
possess a natural immune system, and pathogen contamination
in
mass manufacturing phase can potentially present an infectious
disease
risktoagreaternumberofpatients.