Biology Reference
In-Depth Information
TABLE 5.2
STEC adherence factors—cont'd
Potential adhesins
Function
Porcine attaching-effacing
associated protein (Paa)
Required for the A/E activity by many A/E strains,
including O157:H7 and promotes initial bacterial
adherence (
An et al., 1999
;
Batisson et al., 2003
).
STEC
autoagglutinatingadhesin
(Saa)
Plasmid encoded and isolated from LEE-negative STEC
(
Paton et al., 2001
). Saa-harboring STEC exhibit differential
binding properties to epithelial cells (
Toma et al., 2008
).
Saa positive STEC frequently isolated from bovine rather
than human origin (
Jenkins et al., 2003
).
Flagella
O157:H7 flagella agglutinates rabbit red blood cells,
promotes adherence to mucins I and II and persistence
in chicken in the absence of intimin
(
Best et al., 2005
;
Erdem et al., 2007
).
AdfO
Secreted from T2SS and encoded on the cryptic
prophage CP-933O, AdfO promotes for adherence of
EHEC to cultured HeLa cells (
Ho et al., 2008
).
YodA
AdfO facilitates YodA secretion from pO157-encoded
T2SS and promotes adherence of EHEC to HeLa
cells and colonization of the infant rabbit intestine
(
Ho et al., 2008
).
StcE
A zinc metalloprotease secreted by the T2SS on the
plasmid pO157, cleaves serpin C1 esterase inhibitor
(
Lathem et al., 2002
,
2004
). Reduces the mucous
glycocalyx cell surface barrier and promotes a closer
interaction between the bacterium and host cell
(
Grys et al., 2005
,
2006
).
to bovine gut explants (
Xicohtencatl-Cortes et al., 2007
). Moreover, HCP
generates an antibody response in patients with HUS, suggesting that these
pili are produced during infection (
Xicohtencatl-Cortes et al., 2007
). EspA,
which forms a filamentous appendage from EHEC's T3SS, has been sug-
gested to be an adhesin promoting initial interaction between host cells and
bacteria (
Ebel et al., 1998
). YodA and StcE, two effectors secreted through a
type II secretion system, promote EHEC adherence to cultured monolayers,
as well as during colonization of infant rabbits (
Grys et al., 2005
;
Ho et al.,
2008
). Non-fimbrial EHEC adhesins include OmpA, and have been shown
to facilitate bacterial binding to cultured monolayers (
Torres and Kaper,
2003
). Finally, H7 flagella have been hypothesized to promote adherence
to mucus and extracellular matrix proteins within the host intestinal tract
(
Erdem et al., 2007
).
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