Recombinant probiotics for treatment and prevention of enterotoxigenic Escherichia coli diarrhea.
OBJECTIVE
We have developed a therapeutic strategy for gastrointestinal infections that is based on molecular mimicry of host receptors for bacterial toxins on the surface of harmless gut bacteria. The aim of this study was to apply this to the development of a recombinant probiotic for treatment and prevention of diarrheal disease caused by enterotoxigenic Escherichia coli strains that produce heat-labile enterotoxin.


METHODS
This was achieved by expressing glycosyltransferase genes from Neisseria meningitidis or Campylobacter jejuni in a harmless Escherichia coli strain (CWG308), resulting in the production of a chimeric lipopolysaccharide capable of binding heat-labile enterotoxin with high avidity.


RESULTS
The strongest heat-labile enterotoxin binding was achieved with a construct (CWG308:pLNT) that expresses a mimic of lacto-N-neotetraose, which neutralized > or = 93.8% of the heat-labile enterotoxin activity in culture lysates of diverse enterotoxigenic Escherichia coli strains of both human and porcine origin. When tested with purified heat-labile enterotoxin, it was capable of adsorbing approximately 5% of its own weight of toxin. Weaker toxin neutralization was achieved with a construct that mimicked the ganglioside GM2. Preabsorption with, or coadministration of, CWG308:pLNT also resulted in significant in vivo protection from heat-labile enterotoxin-induced fluid secretion in rabbit ligated ileal loops.


CONCLUSIONS
Toxin-binding probiotics such as those described here have considerable potential for prophylaxis and treatment of enterotoxigenic Escherichia coli-induced travelers' diarrhea.
Paton
Adrienne W
AW
School of Molecular and Biomedical Science, University of Adelaide, South Australia, Australia.
Jennings
Michael P
MP
Morona
Renato
R
Wang
Hui
H
Focareta
Antonio
A
Roddam
Louise F
LF
Paton
James C
JC
D000311:Adrenal Glands / Q000166:cytology; D000818:Animals; D001427:Bacterial Toxins / Q000378:metabolism; D016123:Campylobacter jejuni / Q000235:genetics; D002478:Cells, Cultured; D002772:Cholera Toxin / Q000378:metabolism; D003967:Diarrhea / Q000382:microbiology* / Q000517:prevention & control*; D004768:Enterotoxins / Q000378:metabolism; D004926:Escherichia coli / Q000145:classification* / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins; D016695:Glycosyltransferases / Q000235:genetics; D007082:Ileum / Q000382:microbiology; D008070:Lipopolysaccharides / Q000378:metabolism; D009345:Neisseria meningitidis / Q000235:genetics; D019936:Probiotics / Q000494:pharmacology*; D011817:Rabbits; D011994:Recombinant Proteins / Q000235:genetics
D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D008070:Lipopolysaccharides; D011994:Recombinant Proteins; C034151:heat stable toxin (E coli); D002772:Cholera Toxin; D016695:Glycosyltransferases