RESUMO
Three leptospiral bacterins, produced with different serovars of Serogroup Sejroe, namely the hardjo (bacterin A), wolffi (bacterin B) and guaricura (bacterin C), were evaluated in male hamsters (Mesocricetus auratus) by comparing the agglutinating and neutralizing antibodies titers using microscopic agglutination (MAT) and in vitro growth inhibition (GIT) tests. The immunization schedule was based on two 1.0 mL doses of non-diluted formalininactivated whole culture bacterin given through subcutaneous route with 10-day interval. The challenge was performed ten days after the second vaccine dose, when the animals were inoculated with 0.2 mL of non-inactivated cultures of each serovar through intraperitoneal route. On the 21st post-challenge day (PCD), all animals were bled and their sera were joined in pools (n=8) and tested by MAT and GIT. All vaccinated and control animals presented no clinical signs of leptospirosis after the challenge, but the serovar guaricura was isolated from the kidneys of control animals on the 21st PCD. The MAT results showed cross agglutinins between serovars hardjo and wolffi, and between wolffi and guaricura. The GIT results revealed the presence of cross neutralizing antibodies between serovars wolffi or guaricura against hardjo, wolffi and guaricura. It was found that the tested strain of serovar hardjo did not produce detectable levels of neutralizing antibodies, indicating its poor immunogenicity
Assuntos
Cricetinae , Anticorpos , Cricetinae , Técnicas In Vitro , Infecções por Bactérias Gram-Negativas , Leptospira , Brasil , Testes Sorológicos , SorotipagemRESUMO
Tendo sido comprovada a existência de quatro famílias molecularmente distintas de M. avium (PIG-A, B, C e D) circulando em suínos da regiäo sul do Brasil, e havendo dúvidas a respeito da importância da transmissäo horizontal como mecanismo de manutençäo da doença, o presente teve por objetivo estudar a virulência dessas estirpes, informaçäo importante para o aperfeiçoamento dos métodos de controle. Uma estirpe representante de cada família foi inoculada pela via intra-peritoneal em 48 hamsters com uma dose de 30.000 U.F.C. por animal. Após 2, 13, 26 e 40 dias da inoculaçäo (T1 a T4), 12 hamsters inoculados de cada família foram anestesiados, sacrificados e os agentes foram quantificados no fígado, baço e pulmäo. Os resultados foram expressos em número de U.F.C./g de órgäo. A presença das estirpes foi pesquisada no sangue e também foram realizados exames histológicos. As estirpes PIG-A, B, C e D induziram a formaçäo de lesöes granulomatosas no fígado e baço a partir do segundo dia pós-inoculaçäo e disseminaram-se pela via hemática, alcançando os pulmöes. O baço sempre apresentou maiores contagens de U.F.C., seguido pelo figado e pulmöes. Diferenças entre as estirpes foram constatadas através de análises das contagens de U.F.C de baço (T1: p<0,001; T2: p<0,001; T3: p<0,001 e T4: p<0,001), permitindo a construçäo da seguinte escala de virulência: PIG-B> PIG-A> PIG-D> PIG-C
Assuntos
Animais , Feminino , Cricetinae , Complexo Mycobacterium avium , Infecções por Mycobacterium , Suínos , Tuberculose , VirulênciaRESUMO
Three leptospiral bacterins, produced with different serovars of Serogroup Sejroe, namely the hardjo (bacterin A), wolffi (bacterin B) and guaricura (bacterin C), were evaluated in male hamsters (Mesocricetus auratus) by comparing the agglutinating and neutralizing antibodies titers using microscopic agglutination (MAT) and in vitro growth inhibition (GIT) tests. The immunization schedule was based on two 1.0 mL doses of non-diluted formalininactivated whole culture bacterin given through subcutaneous route with 10-day interval. The challenge was performed ten days after the second vaccine dose, when the animals were inoculated with 0.2 mL of non-inactivated cultures of each serovar through intraperitoneal route. On the 21st post-challenge day (PCD), all animals were bled and their sera were joined in pools (n=8) and tested by MAT and GIT. All vaccinated and control animals presented no clinical signs of leptospirosis after the challenge, but the serovar guaricura was isolated from the kidneys of control animals on the 21st PCD. The MAT results showed cross agglutinins between serovars hardjo and wolffi, and between wolffi and guaricura. The GIT results revealed the presence of cross neutralizing antibodies between serovars wolffi or guaricura against hardjo, wolffi and guaricura. It was found that the tested strain of serovar hardjo did not produce detectable levels of neutralizing antibodies, indicating its poor immunogenicity.
RESUMO
The finding of four clusters of M. avium (PIG-A, B, C and D), typed by the IS1245-RFLP method, infecting the swine population of the south region of Brazil, the possible existence of virulence differences among them, the role of the virulence in the transmission mechanisms of infections and the existence of reasonable doubts regarding the importance of horizontal transmission for swine micobacteriosis, the virulence of these four strains of M. avium were compared. Bacteria from each cluster were inoculated in 48 hamsters by intra-peritoneal route. On the 2nd, 13th, 26th, and 40th days after inoculation, (T1 to T4), 12 animals of each cluster were sacrificed with vapors of ethyl ether and the bacteria were quantified in the liver, spleen and lung. Results were expressed as cfu/g of organ. The presence of the strains was verified in the blood and histological exams were also accomplished. The four strains induced granulomatous lesions in the liver and spleen since 2 days after inoculation and were disseminated to the lungs through the blood stream. The cfu counts from spleen were always bigger them that obtained from liver and lungs. Differences among strains were observed through the analysis of cfu counts from spleen (T1: p; PIG-A>; PIG-D>; PIG-C.
Tendo sido comprovada a existência de quatro famílias molecularmente distintas de M. avium (PIG-A, B, C e D) circulando em suínos da região sul do Brasil, e havendo dúvidas a respeito da importância da transmissão horizontal como mecanismo de manutenção da doença, o presente teve por objetivo estudar a virulência dessas estirpes, informação importante para o aperfeiçoamento dos métodos de controle. Uma estirpe representante de cada família foi inoculada pela via intra-peritoneal em 48 hamsters com uma dose de 30.000 U.F.C. por animal. Após 2, 13, 26 e 40 dias da inoculação (T1 a T4), 12 hamsters inoculados de cada família foram anestesiados, sacrificados e os agentes foram quantificados no fígado, baço e pulmão. Os resultados foram expressos em número de U.F.C./g de órgão. A presença das estirpes foi pesquisada no sangue e também foram realizados exames histológicos. As estirpes PIG-A, B, C e D induziram a formação de lesões granulomatosas no fígado e baço a partir do segundo dia pós-inoculação e disseminaram-se pela via hemática, alcançando os pulmões. O baço sempre apresentou maiores contagens de U.F.C., seguido pelo figado e pulmões. Diferenças entre as estirpes foram constatadas através de análises das contagens de U.F.C de baço (T1: p; PIG-A>; PIG-D>; PIG-C.