Vaccine against E. coli septicaemia in poultry

#The invention relates to a vaccine for protecting poultry against Escherichia coli (E. coli) septicaemia and also to a method for combating E. coli septicaemia in poultry by administering such a vaccine.

#E. coli septicaemia or colibacillosis is a disease which generally occurs in poultry (such as chickens and turkeys) and which is responsible for considerable losses. Characteristic symptoms in birds having this disease are air sac inflammation, pericarditis and perihepatitis. Most of the investigations in this field reveal that more than half of the E. coli strains which are encountered in said sick birds belong to one of three serotypes 01:K1, 02:K1 or 078:K80. In the United States, the serotype 035 is also frequently encountered. It is generally assumed that E. coli septicaemia is a secondary infection which enters the body via the respiratory tract after it has been damaged, for example, by viruses which cause respiratory diseases or by mycoplasmas.

#Little is known of the virulence factors which play a role in the pathogenesis of colibacillosis in poultry. The virulence factors of E. coli strains which play a role in infections in mammals include, for example, attachment fimbriae, toxins and iron-sequestrating mechanisms.

#FIG. 1 illustrates the amino acid sequence of a F11 subunit.

#FIG. 2 presents the hydrophilicity profile of the F11 subunit based on its amino acid sequence.

#In particular, it has been possible to show by investigations that E. coli strains which had been isolated from the affected hearts of chickens with colibacillosis produced fimbriae which were identical to fimbriae of the F11 type which also occur in E. coli strains which cause urinary tract infections in humans.

#It has been possible to demonstrate serologically that the vast majority of the birds having an E. coli septicaemia had been infected with E. coli strains which contain fimbriae of the F11 type.

#Such fimbriae contain subunit proteins having an apparent molecular weight of 18.0 kD according to SDS-PAGE.