Düsseldorf, Univ., Diss., 2002. / Computerdatei im Fernzugriff.

Stuttgart, Univ., Diss., 2003. / Computerdatei im Fernzugriff.

Stuttgart, Univ., Diss., 2003. / Computerdatei im Fernzugriff.

University, Diss., 2005--Würzburg.

Düsseldorf, Universiẗat, Diss., 2002.

Resumo: As bactérias Gram-positivas que contêm ácidos micólicos na parede celular estão classificadas no grupo dos actinomicetos aeróbios ou bactérias corineformes e nocardioformes. Nesse grupo encontra-se o Rhodococcus equi, o qual é relevante à medicina veterinária e humana tal como as micobactérias, causando doença pulmonar que pode mimetizar casos de tuberculose. R. equi é considerado como agente patogênico em potros e tem emergido como oportunista em humanos, especialmente, associado à infecção pelo vírus da imunodeficiência humana. Assim como nos animais, a rodococose humana afeta principalmente, os pulmões, com características clínicas e patológicas, similares à tuberculose pulmonar, em pacientes imunocomprometidos ou não. A identificação de Rhodococcus equi pode ser realizada com base numa variedade de características, fenotípicas, genotípicas e técnicas cromatográficas. Morfologia das colônias, morfologia celular e resistência parcial ao álcool ácido são características chaves para a caracterização inicial. R. equi não oxida ou fermenta carboidratos e nem utiliza acetato, citrato e malonato, como única fonte de carbono, produz catalase, o fator equi (teste de CAMP) e lipase. Não produz amilase, b-galactosidase (ONPG), casease, DNase, esculinase, gelatinase, H2S, indol, lecitinase e oxidase. Demonstra comportamento variável para as provas de nitrato redutase, urease e redução do hipurato, decompõe a adenina, mas não hipoxantina, tirosina e xantina. O método molecular para a identificação de R. equi utiliza a PCR para amplificar um fragmento de 959 pares de base do gene choE, o qual codifica a enzima cholesterol oxidase (COX). Na identificação química, semelhante às espécies do gênero Mycobacterium, membros do gênero Rhodococcus contêm ácidos micólicos plausíveis de serem identificados pela cromatografia... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Gram-positive bacteria, containing mycolic acids in the cellular wall are classified in aerobic actinomycetes or corineform and nocardioform bacteria group. Rhodococcus equi is included in this group, and it is very important to the veterinary and human medicine. Rhodococcus equi is a well-recognized bacterial pathogen in veterinary medicine. First isolated from foals, it causes an important chronic granulomatous pneumonia and lung abscesses. The infection also occurs in humans, often following immunosuppression of various causes. The increased number of human cases reported recently is partly the result of the spread of AIDS but may also reflect the increasing awareness by medical laboratories of this opportunistic pathogen and their improved ability to identify it rather than to dismiss it as a contaminating "micrococcus" or "diphtheroid." R. equi can be identified on the basis of a variety of conventional phenotypic characteristics including microscopic (Gram and acidfast staining) and macroscopic morphologies, growth requirements, metabolism of glucose, and phenotypic molecular characteristics including the presence of mycolic acid composition, which is detected by thin-layer chromatography. The colonial morphology of R. equi is diverse and consists of three major varieties: pale pink and slimy, coral and non-slimy, and pale yellow in color, non-slimy. Colorless colonial variants may also occur. R. equi is a non-motile gram-positive pleomorphic coccobacillus, varying from distinctly coccoid to bacillary depending on growth conditions. All of the rhodococci from clinical specimens are generally weakly acid fast when stained either by the modified Kinyoun method or by the Ziehl-Neelsen method. Regarding biochemical characteristics, the organism is generally biochemically unreactive. It fails to oxidize or ferment carbohydrates, neither uses sodium... (Complete abstract click electronic access below) / Orientador: Clarice Queico Fujimura Leite / Coorientador: Sergio Roberto de Andrade Leite / Banca: Carmo Elias Andrade Melles / Banca: Rosilene Fressatti Cardoso / Banca: Carlos Henrique Gomes Martins / Banca: Antonio Carlos Pizzolitto / Doutor

Orientador: Márcio Garcia Ribeiro / Banca: Carlos Roberto Teixeira / Banca: Jean Carlos Ramos da Silva / Resumo: O presente estudo investigou a ocorrência de Escherichia coli, Rhodococcus equi, Salmonella sp., Coronavírus e Rotavírus nas fezes de Passeriformes e Psitaciformes pertencentes à fauna nacional, de 29 diferentes espécies, sem sinais entéricos. Foram investigados também marcadores de virulência nas linhagens de E. coli (cnf1, hly, papC, papGI, papGII, papGIII, fimH, afa, sfa, iucD, usp, vt1, vt2, eae, k88) e R. equi (genes vapA e vapB). As aves utilizadas no estudo foram provenientes do Centro de Medicina e Pesquisa em Animais Silvestres (CEMPAS) FMVZ - UNESP/ Botucatu, SP, do Parque Zoológico Municipal "Quinzinho de Barros" (PZMQB) de Sorocaba, SP e de criadores particulares com aves registradas no Instituto Brasileiro do Meio Ambiente e dos Recursos Renováveis (IBAMA) da região de Botucatu, SP. Do total de 152 amostras avaliadas foram isoladas 46 (30,26%) linhagens de E. coli das quais 37 (80%) foram provenientes de amostras de Psitaciformes e 9 (20%) de Passeriformes. Houve diferença significante (p<0,05) entre os grupos para o maior isolamento de E. coli nos Psitaciformes. Dentre os marcadores de virulência de E. coli foram detectados os genes fim H (58,69%) e eae (4,34%). Foram isoladas 2 (1,32%) linhagens de R. equi, todas de Psitaciformes. Nestes isolados de R. equi não foram identificados os genes vapA e vapB associados à virulência. Foi encontrado material genético de Rotavírus bovino em três (1,97%) amostras de Psitaciformes. Salmonella sp. e Coronavírus não foram identificados nas aves amostradas. A presença de E. coli, R. equi e Rotavírus em amostras de fezes de aves silvestres, sem sinais entéricos, reforça o potencial destas espécies de servirem como reservatórios de patógenos de eliminação entérica para os humanos, devido à presença destes animais no ambiente domiciliar e peridomiciliar / Abstract: The present study investigated the occurrence of Escherichia coli, Rhodococcus equi, Salmonella sp., Coronavirus and Rotavirus in the feces of Passeriformes and psittaciformes belonging to Brazilian wildlife, from 29 different species, without enteric signs. Virulence markers were also investigated in strains of E. coli (cnf1, hlyA, papC, papGI, papGII, papGIII, fimH, afa, sfa, iucD, usp, vt1, vt2, eae, k88) and R. equi (vapA and vapB genes). The birds used in the study came from the Centro de Medicina e Pesquisa em Animais Silvestres (CEMPAS) FMVZ - UNESP / Botucatu, SP, Parque Zoológico Municipal "Quinzinho de Barros" (PZMQB) Sorocaba, SP and private breeders with birds recorded in Instituto Brasileiro do Meio Ambiente e dos Recursos Renováveis (IBAMA) from Botucatu region, SP. Of the total 152 fecal samples evaluated were isolated 46 (30.26%) strains of E. coli. From these, 37 (80%) were from psittaciformes samples and 9 (20%) of Passeriformes. There was a statistical difference (p <0.05) between groups with greater isolation of E. coli in psittaciformes. Among the virulence markers of E. coli were detected the genes fimH (58,69%) and eae (4,34%). Were isolated 2 (1.32%) R. equi strains, all from psittaciformes. Among these R. equi isolates any vapA and vapB genes associated with virulence were founded. Genetic material of bovine Rotavirus was found in three (1.97%) psittaciformes samples. Salmonella sp. and Coronavírus weren't identified in any of the sampled birds. The presence of E. coli, R. equi and Rotavirus in fecal samples of wild birds without enteric signs from Brazil wildlife, reinforces the potential of these birds as a reservoirs of pathogens of enteric elimination for humans, due to the presence of these animals in the domestic and peridomestic, environment of human / Mestre

No description available.

The pathogenic actinomycete Rhodococcus equi is a facultative intracellular parasite that replicates within macrophages. This ability is dependent on the pVAP virulence plasmid, and more specifically, on the laterally acquired vap pathogenicity island (vap PAI) carried by it. R. equi has two contrasting lifestyles as a soil-dwelling microbe and as an inhabitant of the intracellular macrophage compartment. In the first part of this thesis work we analysed the nature of the signals recognised by R. equi to adapt the expression of the virulence genes of the plasmid during the transition from soil saprotroph to intracellular parasite. The expression profile of virulence plasmid genes in response to temperature and pH in vitro and to the macrophage environment was investigated by microarray analysis. A shift to 37ºC was the main stimulus involved in vap PAI gene activation and macrophage-derived signals did not further modulate the expression of the PAI genes contrary to previous suggestions. In a second part of the thesis we investigated the role of a horizontally acquired island encoding exopolysaccharide biosynthesis in the R. equi saprotroph-intracellular parasite dual lifestyle. Mutational analysis of this locus showed that it is responsible for the typical mucoid colony morphology of R. equi and the ability to produce a polysaccharide capsule. Mutations in the capsule locus favoured macrophage uptake but had no effect on intracellular proliferation and in vivo survival in mice. However, the capsule mutants showed significantly increased susceptibility to desiccation, ultraviolet radiation and heat and were outcompeted by capsulated wild-type R. equi in dry soil. Thus, while having a minor role in virulence, the R. equi capsule appears to be primarily required for survival in soil and to act as a transmission factor. The third part of this work followed the identification of a horizontally acquired locus that encodes pili appendages that promote association with macrophages and colonization of the mouse lung. The ability of a component of this structure, the RplB pilin subunit, to act as a vaccine antigen was investigated in mice and horses. Vaccinated mice produced high levels of anti-RplB IgG and showed significant protection against pulmonary challenge with virulent R. equi. The experimental RplB subunit vaccine proved also to be immunogenic in horses, eliciting a strong IgG response in pregnant mares and foals. We also demonstrated passive transfer of high levels of maternal anti-RplB antibodies from the mares to the foals via colostrum. Our results indicate that the RplB pilin subunit is a promising novel candidate R. equi vaccine antigen.

Reproduction de : Thèse d'exercice : Médecine vétérinaire : Toulouse 3 : 2009. / Titre provenant de l'écran titre. Bibliogr. p. 101-104.