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E. Coli: 255 Enterotoxigenic

Enterotoxigenic E. coli (ETEC) causes diarrhea by binding to intestinal epithelial cells and producing toxins such as LT-I, LT-II, STa, and STb, which increase cAMP and cGMP levels, leading to fluid accumulation. Symptoms include watery diarrhea, vomiting, and dehydration, typically lasting 3-4 days without significant inflammation in the intestine. While generally self-limiting, ETEC infections can be severe in young children, with a low mortality rate.

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27 views1 page

E. Coli: 255 Enterotoxigenic

Enterotoxigenic E. coli (ETEC) causes diarrhea by binding to intestinal epithelial cells and producing toxins such as LT-I, LT-II, STa, and STb, which increase cAMP and cGMP levels, leading to fluid accumulation. Symptoms include watery diarrhea, vomiting, and dehydration, typically lasting 3-4 days without significant inflammation in the intestine. While generally self-limiting, ETEC infections can be severe in young children, with a low mortality rate.

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humaxvyoepwxvfbnop
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Enterotoxigenic E.

coli 255

Fig. 14.5 Mechanism of action for enterotoxigenic LT increases cAMP level, while ST increases cGMP, and
Escherichia coli (ETEC)-mediated diarrhea. After arrival both mediate phosphorylation of CFTR (cystic fibrosis
in the intestine, ETEC binds to the epithelial cells using transmembrane conductance regulator), a chloride ion
colonization factors (CFs) and/or TibA and produces sev- transporter protein, which increases Cl− secretion in crypt
eral toxins including LT-I, LT-II, STa, STb, EAST1, and cells and decreases absorption of Na+ and Cl− by absorp-
ClyA. Mechanism of action of LT-I and STa is presented. tive cells

human and animal origin. The toxin activates Symptoms


cGMP, induces fluid accumulation, and possibly
plays a role in the onset of diarrhea. In addition, ETEC infection does not show any apparent his-
ETEC also produces EatA, a serine protease tological changes in the mucosal layer, and there
autotransporter, which plays a role in pathogene- is little or no inflammation in the intestine. The
sis by damaging the epithelial cell surface. Some symptoms may include watery diarrhea, vomit-
strains of ETEC may secrete ClyA, a cholesterol-­ ing, sunken eyes, massive dehydration, and a col-
dependent cytolysin (CDC), and form pore in the lapse of the circulatory system. Diarrhea lasts for
cell membrane. It binds to cholesterol on the 3–4 days and is self-limited. Diarrhea may be
membrane and shows lytic activity against eryth- lethal in young children and infants, with a mor-
rocytes, macrophages, and HeLa cells. tality rate of less than 1%.

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