[Antigenic structure of strains of Pasteurella multocida]. / Antigenna struktura na niakoi shtamove Pasteurella multocida.

Studied was strain Pasteurella multocida-547 isolated from pigs affected with an acute Pasteurella infection. Serologically and immunologically its antigen was most closely related to the antigen of strain R-473. The main somatic antigen was 0:6, and the antigenic formula was 6:B. Homologous sera were used to demonstrate the presence of subsidiary antigens by which the newly isolated strain differed from strains R-473 (6:B), 1235 (6:E), and 989 (11:B). The immunodiffusion test with proper sera and heat-resistant water-soluble antigens could yield results that correlate with the typing of P. multocida strains by capsule and somatic antigens as established through other methods.

[Improved method for isolating Yersinia enterocolitica]. / Podobren metod za isolirane na Yersinia enterocolitica.

Investigations were carried out to restore and isolate Yersinia enterocolitica from both pure and mixed cultures as well as from sewage waters through enriching and alkaline treatment, employing the method of Aulisio and coll. It was found that the peptone used for the purpose (containing sorbitol, 10.0, yeast extract, 5.0, sodium taurocholate, 2.0, bacto-peptone, 2.0, bacto-tryptone, 2.0, bromthymol blue, 0.007, and 1/15 phosphate buffer, 1000 cm3 at pH = 7) made it possible for Y. enterocolitica to replicate at 4 degrees C in 8 to 10 days and inhibited the development of many other organisms. Enriching the medium at 4 degrees C with the alkaline treatment that followed enabled the isolation of Y. enterocolitica from mixed cultures and sewage waters from milk-processing enterprises in a very high percent of the cases as against enriching at 22 degrees C. Such enriching broth could be used not only for the enriching of Y. enterocolitica at 4 degrees C, but also for the differentiation of pure cultures in culturing at the same temperature.

[Passive hemagglutination test with capsular and somatic antigens of Pasteurella multocida strains isolated from birds]. / Pasivna khemaglutinatsionna reaktsiia s kapsulni i somatichni antigeniot shtamove Pasteurella multocida, izolirani ot ptitsi.

Comparative investigations were carried out with the passive hemagglutination reaction in the serotyping of 14 reference and 34 P. multocida strains isolated from birds with three types of antigens obtained from one and the same bacterial mass: capsular extracts obtained by Carter's method (1), thermostable capsular extracts obtained after Carter and additionally heated at 100 C degrees for one hour (2), thermostable somatic extracts obtained after the additional heading of the depot of bacterial mass, treated after Carter at 100 C degrees for one hour (3). The results obtained with the three extracts correlated fully with each other as established with the passive hemagglutination test. Out of 34 strains 76.47 per cent were typed with the use of two of the capsular extracts, and 97.05 per cent--with the thermostable somatic extracts. Thermostable somatic extracts obtained from reference and field strains of P. multocida showed type specificity according to the classification of Carter. Of the P. multocida strains isolated from birds that succumbed to acute or chronic form of fowl cholera 97.06 per cent were typed as serotype A, and 2.94 per cent--chiefly in the chronic form of the disease--as serotype B. It was found that immunodiffusion conducted with capsular extracts was the most suitable method for the detection of antibodies in the sera of rabbits against P. multocida prior to the animals' hyperimmunization with type cultures.

[Isolation of group D streptococci in pyelitis cystica of swine]. / Izolirane na streptokoki ot grupa D pri tsistopielit po svinete.

A disease was noted among the replacement sows on a pig-breeding complex, exhibiting signs of pyelonephritis, cystitis, and metritis. Bacteriologic studies revealed the presence of streptococci. Streptococcus typing was carried out by means of biochemical, immunodiffusion, and immunoelectrophoretic investigations. The isolated strains were shown to belong to group D--Str. suis. The treatment of HCL-extracts to D-group streptococci with pepsin considerably raised the value of the respective immunoelectrophoretic method in the process of typing.

[Streptomycin-dependent mutants of a Pasteurella multocida strain isolated from poultry]. / Prouchvane na streptomitsin-zavisimi mutanti ot shtam Pasteurella multocida, izolirani ot ptitsi.

A culture of strain Pasteurella multocida 115, isolated from a hen affected with fowl cholera, was treated with 50 mcg/cm3 streptomycin and subjected to selection at an additional treatment with 200 mcg/cm3 of the same antibiotic. A total of 16 streptomycin-resistant mutant strains were obtained. All of them were shown to be avirulent in testing their pathogenicity for mice, however, two of the mutants were of lowered virulence in tests with birds. Fourteen days post vaccination birds that survived were challenged with 1000 LD of the initial wild strain 115. Two of the mutants only did not induce immunity. In cross immunologic testing of the birds with Pasteurella strains X73, 1059, 1662, and 3940 best immunologic properties showed mutants 115.2 and 115.3. In agglutination of sera from the vaccinated birds with HCl--and formalin-treated antigen of strain 115 the titers were low, ranging from 1:10 to 1:40.

[Comparative studies of methods for the bacteriological diagnosis of mastitis in cows]. / Sravnitelni prouchvaniia na niakoi metodi za bakteriologichna diagnostika na mastite pri kravi.

Comparative studies were carried out on some methods and nutrient media used for the isolation and identification of mastitis causative agents. Milk from normal andmastitis-affected udder quarters was aseptically sampled and treated under various conditions. Individual samples were simultaneously seeded in different media. The following conclusions were drawn: 1. Milk samples for the diagnosis of mastitis of a subclinical character can be taken at the beginning and at the end of milking. 2. Direct seedings of milk have equal diagnostic value as those of the sediment. With the former the process of bacteriologic treatment of the samples is shortened in time, and the isolation and differentiation of the mastitis agents is rendered feasible. 3. At the present etiologic structure of the subclinical types of mastitis in this country most suitable has proved the blood agar medium in which almost all mastitis causative agents can be demonstrated. 4. Kartashova's medium and the TKT-medium possess a pronounced selectivity with special reference to streptococci and have higher diagnostic value for farms where streptococcus mastitis is prevailing.