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Biomedical subjects

T Todorov

Publications and source records attributed to T Todorov.

At least 91 records · Page 5Linked to original sources
PubMed1978

[Live vaccine against salmonellosis in swine].

A live vaccine was produced against salmonellosis in pigs, using a mutant strain 3--297 of Salmonella cholerae suis. The vaccine proved fully innocuous at the rate of 1 cm3 to guinea pigs and at 2-5 ml to pigs, and 15 days following injection the vaccinal strains was no longer isolated from the test animals. Guinea pigs injected singly at the rate of 1cm3 of the vaccine and infected on the 12th day with a pathogenic Salmonella cholerae suis strain died up to 12 per cent (the control ones up to 91 per cent). Pigs vaccinated singly or twice at the rate of 2 cm3 and infected on the 20th day (i/v) with a pathogenic strain of Salmonella cholerae suis died up to 14 per cent (the control ones up to 80 per cent).

Animals↗
PubMed1978

[Nitrosoguanidine induction of mutants in Salmonella cholerae suis].

On treatment two strains of Salmonella cholerae suis with nitrosoguanidine and using Ledeberg's contact technique, some 100 colonies of one of the strains were obtained, seven out of which were auxotrophic. These seven mutants were auxotropic, of which three -- to tyrosine, two -- to adenine, one -- to glutamic acid and one -- to histidine. The mutant of the second Salmonella cholerae suis strain is auxotrophic to tyrosine, xanthine and adenine. The colonies of these mutants are smaller. Their growth in MPB is sparse. Their fermentation is deleyed by a higher degree. The mutant, auxotrophic to tyrosine, xanthine and adenine, manifests a delayed fermentation in ramnose and is negative to lysine and to ornithodecarboxylase. The mutant, auxotrophic to tyrosine, possesses a negative argininedehydrolase. Mutants Nos 3,5 and 6 are auxotrophic to adenine, glutamic acid and histidine, respectively, and are with a negative ornithodecarboxylase. Four of the eight mutants were for tested for pathogenicity to white mice. All manifested a decreased pathogenicity, ranging from 1000- to 10,000-fold lower.

Animals↗
PubMed1977

[Experimental transmission of antibiotic resistance in chicks].

Multi-drug resistance of Salmonella heidelberg was transmitted to normal intestinal flora (E. coli organisms were resistant to ampicillin, streptomycin, tetracycline, erythromycin, and oleandomycin. The donor strains of Salmonella heidelberg used in the experiment was a carrier of the following nine markers of resistance: ampicillin, streptomycin, chloramphenicol, kanamycin, neomycin, novobiocin, tetracycline, erythromycin, and oleandomycin. The donor strains of Salmonella heidelberg used in the experiment was a carrier of the following nine markers of resistance: ampicillin, streptomycin, chloramphenicol, kanamycin, neomycin, novobiocin, tetracycline, erythromycin, and oeandomycin, novobiocin, tetracycline, erythromycin, and oleandomycin. The resistance to drugs was transmitted with the oral administration of the donor strain at the preliminary neutralization of the action of hydrochloric acid in the stomah secretion through sodium bicarbonate (1 cm3 of a 10 per cent sol.) an hour prior to feeding the birds with Salmonella heidelberg (1 cm3 of 10(10). In other experiments carboneum tetrachloratum was injected at rates of 0.08 to 0.15 cm3 (acocrting with the body weight of birds) one day prior to infection, followed by the administration of 0.20 to 0.40 cm3 of a 2 per cent solution of omnopon. Escherichia coli organisms acquired new markers of resistance--to chloramphenicol, kanamycin, neomycin and novobiocin. The level of resistance proved equal with that to the donor strain. A total of 1.8 to 5.4 per cent of the intestinal E. coli investigated proved to be carriers of the indicated markers of resitance. Highest level in acquiring markers of multi-drug resistance (13 per cent) showed E. coli organisms isolated from the liver of birds injected additionally with C. tetrachloratum omnopon.

Animals↗
PubMed1977

[Transfer of multi-drug resistance in vivo by salmonellae and shigella in white mice].

The oral infection accomplished by 0.3 cm3 X 10(10) microbial bodies of Salmonella heidelberg and Shigella sonnei in albino mice the pathogens were found to localize in the intestines. The Salmonellae were detected up to the 10th day, and the Shigellae--up to the 14th day. Both Shigella and Salmonella transferred multi-drug resistance to some enterobacteria--E. coli and Proteus as well as to Salmonella typhimurium when the latter was also present in the intestinal tract; of these some 10--40 per cent acquire the multi-drug resistance of Salmonella heidelberg and Shigella sonnei. This type of resistance was most often transferred en bloc for the six, resp., eight markers. On some occasions segregation was observed with the transference of particular markers only.

Animals↗
PubMed1976

[Pathohistological changes in guinea pigs experimentally infected with Yersinia enterocolitica serotype 9].

A total of forty-five guinea pigs were injected subcutaneously with 0.1 cu cm carboneum tetracholoratum each and were infected with Yersinia enterocolitica serotype 9. Part of the animals (31) were treated at the 24th hour following infection with omnopon (a morphine preparation). All infected guinea pigs developed an infectious process manifested by dystrophic and inflammatory changes in the liver, intestine, spleen, lymph nodes and lungs. Those treated with omnopon manifested a more acute infectious process. After the 13--20th day of infection the lesions became more weakly expressed. On the 50th day the inflammatory reaction was observed in the lymph nodes and spleen only. The mortality rate in both groups was about 50 per cent.

Animals↗
PubMed1976

Antibody persistence after surgical treatment of echinococcosis.

Studies on the persistence and levels of antibodies in 280 patients at different intervals following surgery for echinococcosis are described. Post-operative antibody levels were investigated by means of four immunodiagnostic methods, namely, the complement fixation, latex agglutination, indirect haemagglutination, and intradermal tests. After surgical removal of the cysts the tests became negative in some patients, whereas in others they remained positive for many years. As the post-operative period increased, the percentage of positive results fell and this fall was faster in lung echinococcosis than in liver echinococcosis. The titres obtained with the serological tests decreased at the same rate as the percentage of positive results, but the intradermal test remained positive, with an unchanged titre, for many years. In the case of secondary echinococcosis, medium and high titres predominated in all the tests. These immunological investigations during the post-operative period make it possible to evaluate the results of surgery and, to some extent, to clarify the prognosis.

Antibodies↗
PubMed1976

[Sensitivity of E. coli strains to Fredericq-type colicins].

Studied was the spectrum of sensitivity of various Escherichia coli strains to the standard types of colicine after Fredericq. The strains were isolated from dead and emergency slaughtered animals as well as from food products of animal origin. It was found that regardless of the type (colicinogenic and noncolicinogenic) and the origin of the strains almost a monotype spectrum of sensitivity is observed. With but few exceptions the strains proved sensitive to colicine of the types V, D, E+I, F, C, I, J+I, K, Sj, S3+I, S4 and S5. The similarity referred to substantiates the expedience in determining the type of colicine of bacteria in epidemiologic and epizootiologic studies.

Animals↗