The human gastrointestinal tract is a complex ecosystem, in
which resident and transiting bacteria co-exist. This microbiota
fulfils important physiological and metabolic functions which
include maintenance of the gut associated immune system
(Purchiaroni et al., 2013). In some cases, dysbiosis, i.e. imbalanced
intestinal microbiota, occurs. This leads to impairment of the im-
mune function of the gut and chronic gastrointestinal illness can
occur, associated with more or less severe symptoms, referred as
“inflammatory bowel disease” (IBD) (Duboc et al., 2013). The po-
tential role for some pathobionts in establishing and/or exacer-
bating inflammation should not be disregarded (Kamada et al.,
2013) and this may occur in the specific context of Crohn's