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pathotype and the development of strategies to control DAEC infections. On the
other hand, the data indicating that Afa/Dr DAEC strains induce an inflamma-
tory response on polarized intestinal cells (
Betis et al., 2003a
), and the increas-
ing number of studies associating the Afa/Dr adhesin with UTI, should lead to
a renewed interest to understand the immune response of DAEC in humans.
Control and prevention
General guidelines for management of patients with diarrhea are also recom-
mended for DAEC infections. Patients admitted to hospital with diarrhea should
be barrier-nursed, preferably in a side-room, and the infection control depart-
ment should be notified. To prevent UTIs, the most important recommendation
is to practice good personal hygiene. Antibiotic prophylaxis remains unclear
and contradictory (
Greenfield, 2011
).
ADHERENT AND INVASIVE
E. COLI
(AIEC)
Background
Definition and/or classification
Inflammatory bowel disease (IBD), comprises both Crohn's disease (CD) and
ulcerative colitis (UC), and affects approximately 2.6 million people in the US
and Europe (
Loftus, 2004
). CD is a chronic, granulomatous inflammatory condi-
tion characterized by a strong activation of the immune system. Although CD
can affect any site of the intestinal tract, it is more common in the ileum. CD
causes erosions in the inner surface of the intestine known as aphthous ulcers
(
Kaser et al., 2010
), which in severe cases can lead to intestinal obstruction,
among other complications. A complex interplay of genetic and environmental
factors contributes to triggering abnormal immune responses in CD (
Hugot et al.,
2001
;
Ogura et al., 2001
;
Helbig et al., 2012
). However, cumulative evidence
suggests that intestinal bacteria play a major role in the onset and perpetuation
of the disease (
Sartor, 2005
;
Rolhion and Darfeuille-Michaud, 2007
;
Carvalho
et al., 2009
;
Flanagan et al., 2011
). A significant reduction in the gut microbi-
ota diversity with an over-representation of
Enterobacteriaceae
, mainly
E. coli
,
is observed in patients with CD (
Kotlowski et al., 2007
;
Flanagan et al., 2011
;
Joossens et al., 2011
). Although belonging to different serogroups,
E. coli
isolates
from CD patients have highly related ribotype profiles and most of them belong to
the B2 and D phylogroups (
Kotlowski et al., 2007
;
Joossens et al., 2011
). Unlike
non-pathogenic commensal
E. coli
, isolates from CD lesions have been shown to
efficiently adhere to, invade and survive inside epithelial cells and macrophages.
As such, this group of isolates has been collectively named adherent-invasive
E. coli
(AIEC) (
Darfeuille-Michaud et al., 2004
). AIEC have been isolated from
up to one-third of the ileal lesions of CD patients. Thus, AIEC comprise an
E. coli
category associated with persistence in these multifactorial CD. The crite-
ria for inclusion in the AIEC category include: (i) ability to adhere to and invade
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