Biological relationship between F18ab and F18ac fimbriae of enterotoxigenic and verotoxigenic Escherichia coli from weaned pigs with oedema disease or diarrhoea.

Comparative fimbrial expression and adhesion studies were made on enterotoxigenic and verotoxigenic E. coli (ETEC and VTEC) strains isolated from cases of porcine postweaning diarrhoea or oedema disease. F107(F18ab) fimbriae--monitored by polyclonal and monoclonal antibodies and by electron microscopy--were poorly expressed on most VTEC strains. In contrast, 2134P(F18ac) fimbriae were more readily detected on most ETEC strains. The F18ac strains adhered in vivo to ligated intestinal loops in weaned pigs while the F18ab strains did not adhere or adhered weakly. Similarly, the F18ac strains adhered to isolated intestinal brush borders in weaned pigs but the F18ab strains (except for the F107 reference E. coli) did not adhere or adhered weakly in vitro. Neither the F18ab nor F18ac strains adhered to brush borders from newborn pigs. In vitro adhesion of F18ab and F18ac strains was mannose resistant and receptors for F18 seemed to differ from receptors for K88(F4). It is concluded that the antigenic variants of F18 fimbriae (F18ab and F18ac) are biologically distinct. F18ab fimbriae are expressed poorly both in vitro and in vivo and are frequently linked with the production of SLT-IIv and serogroup O139, while F18ac are more efficiently expressed in vitro and in vivo and most often are linked with enterotoxin (STa, STb) production, and serogroups O141, O157.

[Combined parenteral and oral immunization against enterotoxigenic Escherichia coli diarrhea in weaned piglets]. / Kombinovaná parenterální a orální imunizace proti prujmu selat po odstavu vyvolanému enterotoxigenními kmeny Escherichia coli.

Experiments were focused on diarrhea prevention in weaned piglets caused by enterotoxigenic strains of Escherichia coli (ETEC) with colonizing factor 8813. An immunization procedure consisted of intramuscular application of ETEC strain bacterin a day before weaning and a peroral administration of a live culture of nontoxic E. coli strain with the same colonizing factor on the day of weaning. In an experiment on the litter of 10 piglets (six were immunized, four were controls), their intestines were colonized by the nontoxic E. coli strain for 4-7 days (Fig. 1). The challenge peroral infection by virulent ETEC strain demonstrated the protection of immunized piglets from the disease as well as from intestinal colonization by the administered ETEC strain. The same immunization procedure was tested on three pig farms with enzootic occurrence of diarrheas in weaned piglets. On these farms, besides ETEC strain with colonizing factor 8813 (F18) ETEC strains with other colonizing factors (K88, F not specified) were found out in the weanlings - Tab. I. Immunization effect was evaluated according to the rate of mortality of immunized and nonimmunized piglets within a fortnight after weaning. Out of 222 immunized piglets on S farm (Tab. II), 25 piglets died (11.3%), out of 232 nonimmunized animals it was 39 that died (16.8%). As for T farm (Tab. III), 22 piglets (8.6%) died out of 255 immunized animals while 71 out of control 274 piglets died (25.7%). A total of 3,692 were immunized on V farm (Tab. IV). Ninety-four animals died among them (2.5%). Mortality rate in the control group of 6,301 animals was 523 piglets (8.3%).

Colonization factor different from K88, K99, F41 and 987P in enterotoxigenic Escherichia coli strains isolated from postweaning diarrhoea in pigs.

A novel common colonization factor was detected in enterotoxigenic strains of Escherichia coli isolated from intestinal contents of piglets affected with postweaning diarrhoea. This factor was antigenically distinct from the previously described K88, K99, F41, 987P, CFAI, CFAII and Att25 fimbrial antigens. E. coli strains possessing this factor adhered to the pig intestinal brush borders and one strain, used in experimental infection in weanlings, colonized the intestinal epithelium and induced diarrhoea. Examination of 212 toxigenic strains of E. coli isolated from weanlings revealed the presence of the novel common colonization factor in 83 strains, belonging to serogroups O25, O108, O138, O141, O147 and O157. The antigen K88 was detected in 47 strains belonging to serogroups O8, O141, O147 and O149.

[Antibody response in mice, rabbits and pigs in response to vaccination with an inactivated oil vaccine containing rotavirus and Escherichia coli strains with K88, K99 and 987P fimbrial antigens]. / Protilátková odpoved mysí, králikov a prasiat vyvolaná ockovaním inaktivovanou olejovou vakcínou s obsahom rotavírusu a kmenov Escherichia coli s fimbriovými antigénmi K88, K99 a 987P.

In trials with mice, rabbits and weanling piglets, four experimental charges of a combined inactivated oil vaccine against diarrhoeas in mammals were tested: the vaccine was to be implanted to sows and it contained porcine rotavirus (PRV); two charges also contained bovine rotavirus and bacterins of enterotoxicogenic strains of E. coli with protective antigens K88, K99 and 987P. At low starting antibody titres the twofold i.m. implantation of 0.2 ml vaccine stimulated in mice the production of antibodies to reach the average titre value of 1:128 against PRV and of 1:256 against BRV; in rabbits the twofold i.m. implantation of 2 ml vaccine stimulated the antibody development to reach the average titres of 1:508 or 1:500, and in weanlings after the twofold i. m. implantation of the vaccine the titres were 1:1028 or 1:469; in mice agglutination antibodies to antigen K88 had the average value of 1:68, to antigen K99 the value of 1:44 and to antigen 987P the value of 1:8192; in rabbits the respective titres were 1:285, 1:136 and 1:6006 and in pigs 1:570, 1:631 and 1:8192. The antibodies to antigen 987P persisted at the same level in pigs for six months. Even though there was a gradual decrease in the antibodies to antigens K88 and K99, at that time the values were 9.8 times, or 15.2 times higher than the starting values, and only the antibodies to PRV dropped to the pre-vaccination level. Repeated administration of vaccine to pigs after six months from revaccination induced, with the exception of antigen 987P, an increase in antibodies in a fortnight to reach such titres that were recorded after revaccination.

[Objective evaluation of the immunogenic effectiveness of polyvalent vaccines against enteral infections of newborn calves under enzootic conditions]. / Objektivní zhodnocení imunogenní úcinnosti polyvalentní vakcíny proti enterálním infekcím novorozených telat v podmínkách probíhající enzootie.

For evaluating the protective effect of polyvalent vaccine against diarrhoea in new born calves caused by rotaviruses, coronaviruses and enterotoxigenic E. coli the method was selected of mathematical and statistical analysis of the set of data characterizing the most important clinical symptoms of the disease during the first three weeks after birth. In two large-scale breeds with a mass occurrence of diarrhoea of the known etiology the state of health of calves before the vaccine application was compared with the state of health of calves born in the period after the vaccination. The following traits were selected for evaluating the severity of the disease: the age of calf at the beginning of the disease, character and intensity of diarrhoea, length of disease and results of treatment. In all the selected indicators, statistically significant differences were determined pointing to the fact that the vaccine used for increasing the immunity against enteropathogenic viruses and bacteria, applied in high pregnant cows and heifers before parturition, protected the sucking calves and calves fed the milk of their mothers against the disease in the first week after birth. The diarrhoea, occurring in the calves of the vaccinated cows and heifers mostly during the second week of age was easy to treat therapeutically and ended in most cases after a short period of a tea diet. After the vaccination, the death loss in both localities decreased more than eight times.

[A new polyvalent vaccine against enteral infections in newborn calves]. / Nová polyvalentní vakcína proti enterálním infekcím novorozených telat.

The most frequent microbial causative agents of massive diarrheas in new-born calves kept on large cattle farms in the CSSR are rotaviruses, coronaviruses and enterotoxigenic strains of E. coli, manifesting themselves as complicated virus-bacterial infections. An inactivated polyvalent adjuvant vaccine has been developed for the prevention and specific prophylaxis of these enteral infections; the vaccine contains bovine rotavirus, bovine coronavirus and three enterotoxigenic serotypes of E. coli with protective antigen K 99. The rotavirus and coronavirus are propagated on the stable cellular line MDBK and inactivated with 0.2% formalin, the Escherichia strains are submersed in the MINCA culture medium during their cultivation and inactivated with 0.5% formalin. The vaccine was prepared as a blend of the same amounts of rotavirus and coronavirus and of such an amount of bacterin so that 1 ml of the vaccine will contain 10(9) bacteria. One part of oil adjuvant was added to five parts of the virus-bacterial blend and the blend was homogenized in the Ultraturax apparatus. The vaccine is to be used for immunization of pregnant cows and heifers; in these animals it induces the production of specific antibodies to all antigens contained in the vaccine. Its immunogenic effects were checked in 32 calves and 38 cows in the herds with the occurrence of diarrheas caused by both enteropathogenic viruses and enterotoxigenic escherichia. It was demonstrated that the inactivation did not influence in either of the viruses the process of inducing the production of specific antibodies, and the antibody response of the calves and heifers after application of 2 ml of complete inactivated vaccine was equally strong as after application of live vaccine containing only rotavirus and coronavirus. The level of the rotavirus antibodies increased on the average 30 times and 200 times, coronavirus antibodies twice and four times. The antibody response to coronavirus was negatively influenced by the relatively high levels of antibodies before vaccination. The antibody response to antigen K 99 was expressive in all cases.

Use of polyvalent cow colostrum in the prevention of enteric infections in calves and piglets.

Colostrum of cows immunized with a polyvalent vaccine against enteropathogenic strains of Escherichia coli gave good protection to piglets and calves against enteric coli infections. Bovine immunoglobulin (IgG1) and its precipitable fragments persisted in the small intestine of piglets for 6 hours after oral administration. The proteolytic breakdown of porcine colostral IgG2, which occurs predominantly in the small intestine proceeded at a higher rate than that of heterologous bovine colostral IgG1. Colostrum of cows immunized with transmissible gastroenteritis (TGE) virus by intramammary administration protected newborn piglets from virulent TGE virus on oral administration. The prevention of enteric coli infections in suckling piglets and calves in Czechoslovakia is based on vaccination of pregnant cows and sows and on additional passive protection of weanlings by oral administration of dried or liquid immune colostrum or serum of cows vaccinated with polyvalent vaccines prepared from enteropathogenic strains of E. Coli.