V.L.V. Abreu

Serotyping and evaluation of the virulence in mice of Streptococcus suis strains isolated from diseased pigs

A total of 110 strains of Streptococcus suis, isolated from diseased pigs in Brazil were serotyped and analyzed for virulence. Serotyping of the strains resulted in the following classification: 42 strains of serotype 2 (38.2%), 10 strains of serotype 14 (9.1%), seven strains of serotype 9 (6.4%), three strains each of serotype 7 and 11 (2.7%), two strains each of serotype 1 and 8 (1.8%) and one strain each of serotypes 1/2, 3, 5, 6 and 10 (0.9%). Cross reactions among serotypes 1, 14 and 7 were observed in 21 strains (19.1%). Only 41.9% of the strains were lethal for mice using the pathogenicity test.

Immunohistochemical detection of Clostridia species in paraffin-embedded tissues of experimentally inoculated guinea pigs

Blackleg is caused by Clostridium chauvoei, whereas malignant oedema is caused by C. chauvoei, C. septicum, C. sordellii, C. perfringens type A, and/or C. novyi type A. Anti-C. chauvoei, anti-C. septicum, anti-C. sordellii and anti-C. novyi type A polyclonal antibodies were produced in rabbits and purified in a column of DEAE-cellulose. Aliquots of the antisera were conjugated with fluorescein isothiocyanate and the remaining was used for the streptavidin biotin peroxidase technique (SBPT). SBPT was standardized to detect C. chauvoei, C. septicum, C. sordellii and C. novyi type A in formalin-fixed, paraffin-embedded tissues of guinea pigs. SBPT was compared to a fluorescent antibody technique (FAT). Sections and smears of muscle from inoculation area (MIA), heart, liver, spleen and kidney, were obtained for both SBPT and FAT. Cross-reactions between the different Clostridial species were not observed. C. chauvoei and C. septicum were detected in all specimens from the animals inoculated with these microorganisms, while only sections of muscle obtained from all the animals inoculated with C. sordellii and C. novyi type A were positive. The same results observed by the SBPT, were obtained on tissue smears of these microorganisms stained by the FAT. The results indicate that SBPT is suitable for detection of C. chauvoei, C. septicum, C. sordellii and C. novyi type A in formalin-fixed, paraffin-embedded tissues of guinea pigs.

Enterotoxemia em bovino

This report describes a case of bovine enterotoxaemia in Morro da Garca, Minas Gerais, Brazil. Clostridium perfringens type D was isolated in pure culture and was characterized by biochemical reactions and PCR. By the mouse neutralization test, the presence of epsilon toxin from intestinal content was detected.

Diarréia em leitões lactentes por Clostridium perfringens tipo A em granjas tecnificadas nos estados de Minas Gerais e São Paulo

Diarrhea in suckling piglets caused by Clostridium perfringens type A was diagnosed in industrial (technified) swine farms of the states of Minas Gerais and Sao Paulo (Brazil), based on isolation and identification of bacterium by biochemical tests, detection of alpha toxin in animal bioassays, and PCR. This seems to be the first report of clostridial enterotoxaemia in piglets by C. perfringens type A in Brazil and allowed specific procedures to control the disease.

Eficácia de vacinas comerciais contra clostridioses frente ao desafio com Clostridium sordellii

Twelve commercial vaccines against clostridiosis commercialized in Brazil which have in their composition Clostridium sordellii were evaluated for efficacy. A standard monovalent bacterin was used as a reference test. Two of the tested vaccines (16.6%), codified as T6 and T8, gave the same results as the standard bacterin, protecting all the challenged animals. One vaccine (8.3%), codified as T10, after being retested was considered efficient. The remaining vaccines (75%), codified as T1, T2, T3, T4, T5, T7, T9, T11 and T12, were considered inefficient.

Production and purification of beta-toxin from Clostridium perfringens type C

type C beta-toxin is involved in necrotic enteritis in humans and other animals. Despite having a worldwide distribution, so far, cases of that disease have not been reported in Brazil. Its diagnosis is most commonly obtained through the serum neutralization test in mice, which requires long periods of observation and large numbers of animals (El Idrisi and Ward, 1992). Regarding the

Perfil sorológico das amostras de Clostridium botulinum tipos C e D utilizadas para produçäo de imunógenos no Brasil

Aiming to the serological evaluation of three strains of C type and three strains of D type Clostridium botulinum used for the production of vaccines in Brazil, the neutralization effectiveness and serological homology in each type were determined. The rate of effectiveness showed the same tendency for both types. The relative antitoxin consumptions were proportional at levels of 20, 200 and 1000 LD50 , verified through neutralization curves which presented similar profiles. The quantification of the antitoxin consumption and variation, which was an expression of serological homology degree, reflect a relative similarity between the strains, and resulted in 80 to 91.5% cross-neutralization of the antigenic structure for the samples of C type and 85 to 95% for the samples of D type. The results showed that the strains behaved as serological variants at the test levels of 20, 200 and 1000 DL50.