Navegando por Palavras-chave "Mycobacterium avium"

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    Análise do comportamento de variantes fenotípicas de cepas de Mycobacterium avium em animais e macrófagos
    (Universidade Federal de São Paulo (UNIFESP), 2006) Oliveira, Rosangela Siqueira de [UNIFESP]; Leão, Sylvia Cardoso [UNIFESP]
    Mycobacterium avium é uma bactéria ambiental e na classificação de patogenicidade está incluída entre as micobactérias potencialmente patogênicas, pois se trata de um patógeno oportunista em animais e humanos. O interesse em estudar fatores de virulência e patogenicidade destas bactérias aumentou após o isolamento de M. avium em amostras de pacientes portadores do vírus da Imunodeficiência Humana (HIV). O objetivo deste estudo foi isolar variantes de colônias de sete cepas de M. avium isoladas de fontes humanas e animais, caracterizadas molecularmente em nosso laboratório e avaliar o comportamento e a capacidade de multiplicação das variantes fenotípicas em experimentos com animais (hamster) e cultura de células (macrófagos). Nos cultivos iniciais, cinco das sete cepas (71,4 por cento) apresentaram variantes de colônias OP e TL e duas cepas (28,6 por cento) não apresentaram variações no fenótipo das colônias. As colônias OP recuperadas dos baços dos animais inoculados mantiveram a mesma morfologia, branca opaca e lisa, enquanto que houve alteração na mortologia nas variantes TL, de lisa transparente para rugosa transparente (TL-Rg). As variantes mantiveram a mesma identificação original por PRA-hsp65 e a mesma tipificação por RFLP-IS1245 após a passagem por animais. Com todas as cepas houve maior recuperação de UFC por grama de baço e maior índice de multiplicação intracelular com a variante TL quando comparada à variante OP. Foi avaliado o percentual de células infectadas nos dias O e 7. Houve aumento no percentual de macrófagos infectados no dia 7 com todas as cepas, com diferença estatisticamente significante em 5 das 12 variantes das cepas estudadas. Quanto ao número de bacilos por macrófago infectado, foi observado que no dia O a maioria dos macrófagos infectados com as variantes OP e TL albergaram de 1 a 15 bacilos enquanto que no dia 7 a quantidade de bacilos que os macrófagos albergaram foi distribuída em freqüências de 1 a mais que 50. Com todas as cepas, a variante TL apresentou uma tendência de distribuição nas freqüências mais elevadas quando comparada à distribuição da variante OP no dia 7. A variante TL das cepas do estudo apresentou maior capacidade de sobrevivência e multiplicação em experimentos "in vivo" e "in vitro".
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    Avaliação da virulência em hamsters (Mesocricetus auratus) de estirpes de Mycobacterium avium presentes na população de suínos do sul do Brasil
    (Faculdade de Medicina Veterinária e Zootecnia / Universidade de São Paulo, 2002-01-01) Oliveira, Eugenia Márcia de Deus; Morais, Zenaide Maria; Tabata, Rosana; Dias, Ricardo Augusto; Oliveira, Rosângela Siqueira de; Leao, Sylvia Cardoso [UNIFESP]; Morés, Nelson; Guerra, José Luiz; Vasconcellos, Sílvio Arruda; Ferreira, Fernando; Pinheiro, Sonia Regina; Balian, Simone Carvalho; Ferreira Neto, José Soares; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP); Embrapa Centro Nacional de Pesquisa em Suínos e Aves
    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<0,001; T2: p<0,001; T3: p<0,001 and T4: p<0,001), allowing the construction of the following virulence scale: PIG-B> PIG-A> PIG-D> PIG-C.
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    Caracterização de um plano plasmídio conjugativo de mycobacterium avium
    (Universidade Federal de São Paulo (UNIFESP), 2016-03-30) Machado, Gabriel Esquitini [UNIFESP]; Leao, Sylvia Luisa Pincherle Cardoso [UNIFESP]; http://lattes.cnpq.br/0390661714924664; http://lattes.cnpq.br/8949906350799877; Universidade Federal de São Paulo (UNIFESP)
    Objective: Characterization of the pMA100 conjugative plasmid from Mycobacterium avium, identifying its replication origin and conjugation mechanism. Material and Methods: To identify and describe the main components of pMA100, assembly and annotation were carried out coupled with bioinformatics analysis and review of literature. Possible regions containing the origin of replication were identified, considering characteristics already described for replication origins of other mycobacterial plasmids, and cloned by the construction of E. coli-Mycobacterium shuttle plasmids. Six recombinant plasmids were constructed, three involving the rep1 gene and different upstream regions, and three involving the rep2 gene and different upstream regions. Rapidly growing mycobacteria (RGM) (M. smegmatis mc2155, M. abscessus ATCC 19977) and slow growing mycobacteria (SGM) (M. bovis BCG Moreau and Pasteur) were transformed with the six recombinant plasmidsconstructed. Additionally, a conjugative mechanism of pMA100 was proposed based on bioinformatics analyses and literature review of its components. Results: Bioinformatics analyses showed that the pMA100 plasmid belongs to a family of SGM plasmids which is characterized by the presence of three conserved regions, related to the conjugation mechanism of this plasmid: one secretion system type 4 (SST4) locus, one secretion system type 7 (SST7) locus and the exonuclease V gene. The existence of a functional replication origin in pMA100 was proven with two constructions involving the rep1 gene: rep1-2539 and rep1-1708. Construction rep1-2539 generated transformant colonies with M. smegmatis mc2155, M. bovis BCG Pasteur and Moreau, while construction rep1-1708 generated transformant colonies only with M. smegmatis mc2155. Conclusions: The pMA100 plasmid has a functional origin of replication in the upstream region of the rep1 gene, and this plasmid conjugation probably occurs by a novel mechanism involving components of SST4, SST7 and exonuclease V.
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    Caracterizacao moleculart de amostras de Mycobacterium avium isolados de suinos na regiao sul do Brasil
    (Universidade Federal de São Paulo (UNIFESP), 1999) Sircili, Marcelo Palma [UNIFESP]
    Mycobacterium avium e um dos membros do complexo M. avium (MAC). Bacterias pertencentes a este complexo sao ubiquitarias, podendo ser isoladas de fontes ambientais, animais e humanas. Em suinos, a infeccao por M. avium e considerada um problema frequente quando estes animais estao em regime de confinamento para producao em larga escala. Na regiao Sul do Brasil observou-se um incremento na ocorrencia de micobacterioses nos ultimos anos. Os segmentos envolvidos se uniram para elaborar um programa de controle. Este projeto teve como objetivos identificar as amostras micobacterianas isoladas nessa regiao e caracterizar as amostras de M. avium atraves de RFLP. Foram estudados 112 isolamentos obtidos de 90 animais. Cento e sete foram identificados como M. avium, 4 como M. bovis e l como Nocardia, de acordo com resultados obtidos com PRA, AccuProbe, amplificacao de DTl, DT6, ISl245 e ISl3ll e identificacao bioquimica, Foram identificadas 2 novas variantes alelicas de M. avium por PRA. Foi identificado um grupo de amostras cujo DNA nao pode ser amplificado com primers derivados de ISl245. Experimentos de RFLP revelaram a existencia de 4 agrupamentos com padroes similares. Um destes agrupamentos incluiu 27 amostras isoladas de diferentes municipios da regiao. Os experimentos de RFLP revelaram tambem a existencia de infeccoes multiplas por diferentes cepas de M. avium em dois animais. Sera necessario determinar se existem diferencas em virulencia e resistencia a fatores ambientais das cepas incluidas nos agrupamentos que expliquem sua disseminacao nestes animais
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    Comparação de perfis genéticos de cepas de Mycobacterium avium isoladas de humanos e animais
    (Universidade Federal de São Paulo (UNIFESP), 2001) Oliveira, Rosangela Siqueira de [UNIFESP]; Leão, Sylvia Cardoso [UNIFESP]
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    Comparison of methods for mycobacteria isolation from swine feces
    (Sociedade Brasileira de Microbiologia, 2007-12-01) Oliveira, Eugenia Márcia de Deus; Rodriguez, César Alejandro Rosales; Rocha, Vivianne Cambuí Mesquita; Ambrosio, Simone Rodriguez; Ohara, Patrícia Miyuki; Amaku, Marcos; Ferreira, Fernando; Dias, Ricardo Augusto; Leao, Sylvia Cardoso [UNIFESP]; Ferreira Neto, José Soares; Universidade Federal da Bahia Escola de Medicina Veterinária Departamento de Medicina Veterinária Preventiva; Universidade Federal de São Paulo (UNIFESP)
    Swine mycobacteriosis is an important cause of carcass condemnation at abattoirs. One of the best ways to recognize the etiologic agent involved, in live animals, is the fecal isolation, as 94% of the lesions are located in the digestive tract. Therefore, the goal of the present study was to compare the performance of four decontamination methods followed by inoculation in three different culture media, totalizing twelve procedures of mycobacteria search from swine fecal samples experimentally contaminated. The swine feces were artificially contaminated with 0.02 g of Mycobacterium avium, PIG-B strain, and subjected to mycobacteria isolation trial. The protocols used were: 1) modified Petroff or basic method; 2) modified Lowenstein-Jensen or acidic method; 3) modified Petroff or basic method with re-suspension in Amphotericin B; 4) modified Lowenstein-Jensen or acid method with re-suspension in Amphotericin B, followed by inoculation in Petragnani, Lowenstein-Jensen and Lowenstein-Jensen medium with antibiotics (Penicillin G and Nalidixic acid). There was a difference (p<0.05) between the mycobacterial recovery percentages from swine feces. The acid method with re-suspension in Amphotericin B solution and inoculation in Lowenstein-Jensen medium with antibiotics showed the best results (87% of mycobacteria recovery).
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    Estudo da capacidade de apresentação de antígenos e da interação com Mycobacterium avium em modelo in vitro de células epitelióides
    (Universidade Federal de São Paulo (UNIFESP), 2005) Chinen, Ludmilla Thome Domingos [UNIFESP]; Carneiro, Célia Regina Whitaker [UNIFESP]
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    Estudo do mecanismo de transferência horizontal da sequência de inserção IS1245, específica de Mycobacterium avium, para Mycobacterium kansasii
    (Universidade Federal de São Paulo (UNIFESP), 2009-08-26) Rabello, Michelle Christiane da Silva [UNIFESP]; Leao, Sylvia Cardoso [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Mycobacterium avium and Mycobacterium kansasii are non-tuberculous mycobacteria frequently isolated in infections from HIV positive patients. In a previous study from our laboratory, a mixed culture of M. avium and M. kansasii from a bone marrow isolate of an HIV positive patient was studied. The analysis of isolated colonies allowed the detection of the insertion sequence IS1245, specific from M. avium, in M. kansasii. The presence of this element in M. kansasii was confirmed by PCR-IS1245, RFLP-IS1245 and sequencing. The objective of this study was to investigate the mechanism of transference of the IS1245 to M. kansasii. A band of approximately 100 kb was detected by PFGE in colonies of M. avium and M. kansasii from this mixed culture. Tests of mobility of this DNA band in PFGE gels, in different running conditions, and tests with exonucleases and topoisomerase I demonstrated that this band was a linear plasmid (pMA100) with proteins covalently linked to the 5’ ends. These findings led to the hypothesis that the pMA100 plasmid was responsible for the natural transference of the IS1245 element from M. avium to M. kansasii by conjugation. Experiments performed in vitro reproduced the conjugation event, not only with the M. kansasii strain from the mixed culture, but also with other two unrelated M. kansasii strains. The insertion sequence was stably maintained in the M. kansasii genome after 10 subcultures and its replicative transposition in M. kansasii was also observed. For the first time the natural horizontal gene transfer between different species of mycobacteria has been demonstrated.
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    Recombinant interleukin-4-treated macrophages, epithelioid cell surrogates, harbor and arrest Mycobacterium avium multiplication in vitro
    (Elsevier B.V., 2006-04-01) Chinen, Ludmilla Thome Domingos [UNIFESP]; Cipriano, Ivone Martins [UNIFESP]; Oliveira, Rosangela Siqueira de [UNIFESP]; Leao, Sylvia Cardoso [UNIFESP]; Mariano, Mario [UNIFESP]; Carneiro, Celia Regina Whitaker [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Discipline Dev Biol
    Our group has previously described that murine peritoneal macrophages treated in vitro for 7 days with recombinant interleukin-4 (rIL-4) acquire morphological and functional characteristics of epithelioid cells (ECs) found in granulomatous lesions. Although EC function has not been clarified so far, it has been suggested that these cells could present antigens and control multiplication of mycobacteria. These aspects have been addressed here using in vitro EC surrogates. Using immunocytochemistry and immunofluorescence methods, we have observed an increased expression of CD11b, CD54, CD86 and CD40 molecules on rIL-4-treated macrophages when compared to untreated ones. Cytokine-treated cells were less phagocytic for latex beads (P < 0.03) and more pinocytic for dextran particles than untreated macrophages. T-cell lymphoproliferation assays using ovalbumin (OVA) and Mycobacterium avium as antigens showed that both cultured macrophages were equally efficient as antigen presenting cells (APCs). However, M. avium antigens were better presented in vivo by EC surrogates (P < 0.01). Both macrophage cultures were similarly infected by M. avium. However, while the infection level was maintained in the cytokine-treated population, untreated macrophages showed a progressive increase in the number of bacilli/cell with time (P < 0.01) and a reduction of about 65% in cell population. After 96 h of M. avium infection, untreated cells secreted higher amounts of tumor necrosis factor-alpha (P < 0.005) while rIL-4-treated macrophages showed higher, although not significant, transforming growth factor-beta production. Also, EC surrogates produced less nitric oxide than control macrophages (P < 0.05). Hence, EC surrogates restrain M. avium growth and act as APCs in vitro and in vivo. (c) 2006 Elsevier SAS. All rights reserved.