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Biomedical subjects

A Dam

Publications and source records attributed to A Dam.

At least 55 records · Page 3Linked to original sources
PubMed1977

"R"-living vaccine against colibacillosis. Communication I.

After our estimation of the LD100 of enteropathogenic E. coli 0149 and 0138 (and their toxins) in rabbits and mice (intravenously and subcutaneously or intraperitoneally, respectively), rabbits and mice were vaccinated subcutaneously by the living "R" 0149 vaccine. All animals showed resistance against the LD100 of both E. coli serotypes; this state of resistance lasted 1-5 months in rabbits, and 1-3 months in mice. Sera of vaccinated rabbits showed bactericidal activity against both E. coli serotypes. The R-E-system of rabbits which were immunized by the endotoxin of "R" 0149 living vaccine, showed mobilization of immunocytes. The vaccine seems to be harmless to newborn piglets after oral vaccination; 2 colostrum deprived piglets, despite vaccination at once after birth, did not survive the big chalenge with 100 ml of broth culture of E. coli 0149 "S" (anapylactic shock). But in comparison to 1 not vaccinated control piglet, the two piglests showed only few E. coli colonies in the intestines, while the intestine of the control animal was very massively colonized by the virulent strain. As the immunizing potency of the "R" 0149 living vaccine was clearly shown in rabbits and mice, further investigations on piglets (newborns, weaning epriod, and after weaning) are needed, to state whether the value of this vaccine corresponds with the immunizing potency shown in our preliminary experiments. The "R"-vaccine seems to open some perspective in colibacillosis prevention of children and animals, and therefore it deserves our attention.

Animals↗
PubMed1975

Polyserositis in pigs due to generalized Escherichia coli infection.

A fibrinous polyserositis syndrome due to generalized Escherichia coli infection in pigs was observed in 13 out of 17 systematically monitored herds. The mortality rate was approximately 0.1% among liveborn pigs. The occurrence was usually sporadic but a minor enzootic was observed in one herd. Most of the affected pigs succumbed during first or second week of life but cases were observed throughout the suckling period. The clinical signs included marked depression, anorexia, rough haircoat, laboured respiration and death in two to five days. Predominant gross pathological lesions were signs of septicaemia and a voluminous, gelatinous and fibrinous exudate in the pleural, the pericardial and the peritoneal cavities. Frequently also a firbinous polyarthritis and a fibrinous pneumonia were present. The majority of the isolated invasive E. coli strains were nonhaemolytic. Serologically 11 different E. coli O groups were encountered. O group most frequently represented was 020. None of the examined E. coli strains belonged to the serogroups which frequently are associated with enteropathogenicity in pigs.

Animals↗
PubMed1975

[Mucous (M) mutants of enteropathogenic, septicemic and saprophytic E. coli (author's transl)].

Mucoid M mutants of enteropathogenic (for suckling pigs), septicemic (for calves), and saprophytic E. Coli were subject of the study. The characteristics of the M colonies have been listed in Table 1. Both spontaneously occurring M mutants which had been isolated by culturing of E. coli strains (S form) in normal horse serum (undiluted) for several weeks were observed. Enzymatic-biochemical tests revealed the existence of M mutants with full enzmatic activity which are identical with the homologous S and R forms. There were also M mutants exhibiting a considerably reduced enzymatic activity. Antigenic-serological analysis (agglutination) exhibited M mutants which were agglutinated by the homologous sera, at low and high titres. In contrast to this, one group of M mutants was found not to be agglutinable, despite autoclaving at 120 degrees C for 2 hours. Some mutants cultured in broth for several weeks were re-exhibiting S colonies of full biochemical activity and full antigen reactivity against homologous agglutinating sera.

Agglutination Tests↗
PubMedDate not supplied

[Characteristic of endotoxin (and haemolysin) for S-, R- and M-forms of the enteropathogenic "E. coli" (author's transl)].

Endotoxins of E. Coli O 149, IN S-, R- and M-forms, were examined in comparison. Gas chromatography showed only quantitative differences in the amount of volatile fatty acids. Electrophoresis of immunsera and bacteriostatic potency of sera, showed the immunogenicity of those 3 endotoxins, in sequence: S leads to R leads to M. Endotoxin of enteropathogenic E. coli O 149 provokes haemorrhagic effects in bones marrow of mice. Endotoxin influences the reticulo-endothelial system (mobilization of immunocytes). Endotoxin does not provoke any changes in "ligated loop tests'.

Animals↗