Experimental enterotoxin-induced Escherichia coli diarrhea and protection induced by previous infection with bacteria of the same adhesin or enterotoxin type.

Abstract

The diarrheal response to an initial and a second infection with Escherichia coli expressing various enterotoxins (the heat-stable toxin [ST] alone or in combination with the heat-labile toxin [LT]) and colonization factor antigens (CFA/I, CFA/II, or E8775-type) was studied in the reversible tie adult rabbit diarrhea model. An initial infection with high doses (1 X 10(10) to 5 X 10(11) bacteria) of the various strains regularly induced diarrhea which was usually self-limiting (only 7 of 85 animals died). The diarrheal response to equally effective doses of different strains producing both ST and LT (ST/LT) did not differ significantly with serotype or colonization factor antigen. ST/LT-producing strains appeared to induce severe disease more regularly than ST-producing strains carrying the same adhesin. Previous infection with CFA/I-carrying, ST/LT-producing E. coli protected all animals reinfected with an otherwise highly diarrheogenic dose of the same strain as well as against challenge with a CFA/I-carrying, ST/LT-producing strain with different O-, K-, and H-antigens. Fecal excretion of bacteria was also significantly reduced in the protected animals, although not completely eliminated. When only one of the two antigens, CFA/I and LT, was shared by the immunizing and rechallenge strains, partial protection was evident consistent with independent antibacterial (anti-CFA) and antitoxic (anti-LT) immune mechanisms. Oral immunization with purified CFA/I significantly reduced fluid secretion in intestinal loops infected with CFA/I-carrying enterotoxigenic bacteria.

• Authors: C M Ahrén, A M Svennerholm
• Journal: Infection and immunity (Infect Immun) Vol. 50 Issue 1 Pg. 255-61 (Oct 1985) ISSN: 0019-9567 [Print] United States
• PMID: 2864313 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Adhesins, Escherichia coli
• Antigens, Bacterial
• Bacterial Proteins
• Endotoxins
• colonization factor antigens
• Fimbriae Proteins

Topics

• Adhesins, Escherichia coli
• Adhesiveness
• Animals
• Antigens, Bacterial (immunology)
• Bacterial Proteins (immunology)
• Diarrhea (chemically induced, immunology, microbiology)
• Disease Models, Animal
• Endotoxins (toxicity)
• Escherichia coli (immunology, pathogenicity)
• Feces (microbiology)
• Female
• Fimbriae Proteins
• Fimbriae, Bacterial (immunology)
• Immunization
• Male
• Rabbits