RESUMEN
The production of enterotoxins by 237 hemolytic strains of Escherichia coli isolated from pigs was determined with the use of CTE in CHO. Vero and Hela cells and ILT. More frequent (p less than 0.01) production of enterotoxins, determined by ILT, was found for the serotypes being pathogenic for the animals (63.8% of the strains). No correlation between intensity of ILT and particular serotype was observed. Both the serotypes pathogenic for pigs and other serotypes produced LT enterotoxins and ST toxin. The frequency of LT enterotoxin production was statistically insignificant compared to the frequency of ST enterotoxin production by strains with serotypes pathogenic for the pigs. Strains of E. coli producing only enterotoxin ST belonged both to the pathogenic serotypes as well as to other hemolytic serotypes. The cytotoxic activity of supernatants of E. coli strains with different serotypes isolated from pigs in Vero and Hela cells and simultaneous CTE in CHO cells was observed. This suggests the production by the strains of enterotoxin LT and cytotoxin VT. Seven out of the 96 isolates showing CTE in CHO cells gave no reaction in the ILT in pigs. This suggests the production by these isolates of a toxin (toxins) differing from the E. coli enterotoxins.
Asunto(s)
Toxinas Bacterianas/biosíntesis , Enterotoxinas/biosíntesis , Proteínas de Escherichia coli , Escherichia coli/metabolismo , Animales , Línea Celular , Efecto Citopatogénico Viral , Células HeLa , Porcinos/microbiología , Células VeroAsunto(s)
Antígenos Bacterianos/análisis , Antígenos de Superficie/análisis , Diarrea/veterinaria , Enterotoxinas/análisis , Infecciones por Escherichia coli/veterinaria , Escherichia coli/clasificación , Sepsis/veterinaria , Enfermedades de los Porcinos/microbiología , Animales , Diarrea/microbiología , Escherichia coli/patogenicidad , Infecciones por Escherichia coli/microbiología , Antígenos O , Sepsis/microbiología , Serotipificación , PorcinosRESUMEN
Different vaccines against Escherichia coli diarrhea of piglets were applied parenterally in pregnant sows at an industrial fattening farm. The following vaccines were used: vaccine No. 1 with non-complete Freund's adjuvant. Tween 80 and Arlacel A, comprising O149:K91,K88; O139:K82; O8:K87,K88; O141:K85,K88; and O64:K? E. coli serotypes; vaccine No. 2 with paraffin oil instead of Freund's adjuvant, comprising the same E. coli serotypes as the vaccine No. 1; stable specific vaccine with 10% aluminum hydroxide, based on E. coli serotypes most frequently isolated from piglets which died at the farm (O149:K91,K88; O8:K87,K88; O20:K17; O64:K?); Gletvax K88 (Wellcome) and NOBI-VAC LT-K88 (Intervet International). The number of piglets which died up to the moment of weaning in comparison to the number of born ones was considered as an indicator of acquired protection. It was found that the most effective in conferring protection against E. coli diarrhea were: vaccine No. 1 and NOBI-VAC. The differences in the mortality rate between piglets originating from sows vaccinated with these vaccines and those from unvaccinated ones were statistically significant (P less than 0.05). No significant differences were noted between controls and animals vaccinated with the remaining vaccines.
Asunto(s)
Vacunas Bacterianas/inmunología , Diarrea/veterinaria , Infecciones por Escherichia coli/veterinaria , Escherichia coli/inmunología , Inmunidad Materno-Adquirida , Enfermedades de los Porcinos/prevención & control , Animales , Animales Lactantes , Vacunas Bacterianas/administración & dosificación , Diarrea/prevención & control , Infecciones por Escherichia coli/prevención & control , Femenino , Inyecciones Subcutáneas , Embarazo , Porcinos , Vacunas Atenuadas/administración & dosificación , Vacunas Atenuadas/inmunologíaRESUMEN
Serotypes of E. coli strains isolated from piglets, which died with symptoms of diarrhea in 9 swine industrial farms, were determined. Large numbers of serotypes (from 16 to 27) in individual farms were detected. The sets of serotypes from 9 investigated farms differed among each other significantly, depending on the farm and time of examination. It was found that more than one serotype of E. coli may exist in the pig body and contribute to the development of disease. The predominant serotypes, i.e. those comprising more than 10% of serologically determined strains, were found to exist in 6 of the investigated farms and not in the remaining ones. Among the predominant serotypes, particularly important seem to be strains with K88 antigen. For prophylaxis of piglet colibacteriosis in industrial farms in Poland two vaccines for sows are recommended: one containing the K88 antigen only and the other the following serotypes: 0149:K91,K88; 020:K57; 020:K83; O157:K88; 01:K1; 0136:K78; 024:K?; 078:K80 and 0118:K? Strains belonging to these serotypes were the most prevalent in our strain collection.