Perspective of Use of Vaccines for Preventing Enterotoxigenic Escherichia coli (ETEC) Diarrhoea in Humans
from: Pathogenic Escherichia coli: Molecular and Cellular Microbiology (Edited by: Stefano Morabito). Caister Academic Press, U.K. (2014)
Enterotoxigenic Escherichia coli (ETEC) strains are the leading bacteria that cause diarrhea to young children living in the developing countries and children and adults traveling to these areas. ETEC strains produce adhesins that mediate bacteria initial attachment to host epithelial cells and subsequent colonization at host small intestines, and enterotoxins including heat-labile toxin (LT) and heat-stable toxin (STa) that disrupt fluid homeostasis in host epithelial cells to cause electrolyte-rich fluid hyper-secretion and diarrhea. As country-wide implementation of clean drinking water and effective sanitation systems, which can effectively limit ETEC infections, are still an out of reach goal in many developing countries, vaccination is the most practical prevention approach. Vaccines inducing host anti-adhesin immunity to block ETEC attachment and colonization and also antitoxin immunity to neutralize enterotoxicity are considered optimal against ETEC diarrhea. However, although a cholera vaccine (Dukoral®) that stimulates anti-CT immunity provides short-term cross protection against ETEC diarrhea for travelers, vaccines effectively protecting against ETEC are currently still lacking. Vaccines under development are whole-cell oral vaccines and intend to stimulate intestinal mucosal immunity, and newer experimental ETEC vaccine candidates are aimed to provide long lasting and more broad-based protection read more ...