Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2009. / Härtill 5 uppsatser.

Johne’s disease (JD) in cattle is a disease of economic importance caused by Mycobacterium avium subspecies paratuberculosis (MAP). Studies were conducted to estimate the losses due to lower weaning weight of beef calves from MAP test-positive dams, to compare the perceptions of producers and veterinarians on the burden and economic aspects of MAP infection in cow-calf herds, and to evaluate whether testing and culling MAP test-positive cows is economically beneficial. Calves from cows with strong-positive ELISA results were 21.5 kg lighter at weaning compared to calves from ELISA-negative cows. Calves from heavy MAP shedding cows were 58.5 kg lighter, and calves from moderate shedders were 40.8 kg lighter compared to the calves from fecal-culture negative cows. Based on average feeder calf value during 2007 to 2012, these losses corresponded to US $57 per calf for ELISA strong-positive dams, US $157 per calf for heavy fecal shedder dams, and US $109 per calf for a moderate fecal shedder dam. Seedstock producers and the producers enrolled in control programs were more likely to have MAP uninfected herds. The average prevalence reported by producers was 0.8%. Compared to the small herds (<50 head), the average test-positive percentages and estimated prevalences were reported to be higher in medium (50-149) and highest in large (≥150) herds. Veterinarians reported an overall animal level prevalence in their client herds of 5%. Seedstock herds had a lower prevalence and these producers were more likely to enroll in a JD control program. Income lost due to the presence of JD in an infected cattle herd was perceived to be higher by veterinarians. Compared to the veterinarians, seedstock producers were more likely to perceive genetic losses due to culling MAP positive cows. Average annual loss due to JD in a 100 cow herd with a 7% MAP prevalence was $1,644 and $1,747 based on information provided by producers and veterinarians, respectively. Herd level production decreased with increasing prevalence. Compared to test and cull after ELISA or ELISA followed by fecal culture, using fecal culture alone provided the fastest reduction in herd prevalence. Fecal culture was also the least costly alternative based on long-term cumulative costs of an annual test and cull program. Results from the current study suggest that although testing provides faster progress, limiting within herd transmission by sale of all weaned calves and purchasing only low-risk replacements can also reduce prevalence. Results suggest that MAP infection in cows causes significant losses for the calves that are produced. While the knowledge about JD varied between producers and veterinarians, seedstock producers were more enthusiastic about MAP control programs and had lower MAP prevalence in their herds. Overall losses due to MAP infection in the herd might be substantial. It is very costly to control or eliminate MAP once the infection is established in a herd.

La paratuberculose bovine, ou maladie de Johne, est une maladie inflammatoire intestinale chronique provoquant d’importantes pertes économiques chez les producteurs de ruminants du monde entier. Que ce soit chez la vache laitière ou de boucherie, ces pertes sont causées majoritairement par une diminution de la capacité de reproduction, la baisse de production laitière et l’amaigrissement des vaches qui perdent ainsi beaucoup de valeur à l’abattage, en plus d’être sujettes à une réforme précoce. Outre les pertes économiques, le potentiel de transmission à l’humain est un facteur non négligeable en plus d’un risque de contamination de la chaîne alimentaire. Cette maladie est causée par une bactérie intracellulaire obligatoire nommée Mycobacterium avium subspecies paratuberculosis (MAP). II n’existe actuellement aucune stratégie efficace pour combattre l’infection chez les animaux atteints. L’évolution lente de la maladie fait en sorte que les signes cliniques apparaissent tardivement, soit plusieurs années (4 à 7 ans) après l’infection initiale. Au cours de cette progression, les animaux infectés commencent à excréter le pathogène dans leur environnement. Les animaux atteints deviennent infectieux et peuvent contaminer d’autres congénères, ainsi que leur propre veau. Afin de permettre aux producteurs d’éliminer les vaches atteintes avant qu’elles n’atteignent ce stade, il s’avère important d’établir un diagnostic précoce. Actuellement, ce n’est qu’en phase sous-clinique avancée que les tests diagnostiques sont plus sensibles, soit 2 à 3 ans après le début des excrétions fécales chez les animaux infectés. L'incompréhension du manque de sensibilité des tests de dépistage et de l'évolution de cette maladie justifient les efforts de recherche dans ce domaine en vue de mieux comprendre les réponses immunitaires impliquées dans cette maladie. En effet, une meilleure connaissance des processus d’inflammation chronique pourrait aider à développer des outils diagnostiques complémentaires. Nos résultats suggèrent une dérégulation de la réponse immunitaire. Ainsi, en étudiant les composantes et caractéristiques du sang provenant de vaches infectées, il nous a été possible d’observer que les niveaux de cytokines plasmatiques telles l’interleukine 17 et l'ostéopontine se trouvent sécrétées à différents niveaux chez les vaches atteintes de paratuberculose bovine. De plus, l'analyse de la capacité de leur sérum à soutenir efficacement la prolifération des cellules mononucléées du sang périphérique révèle que le sérum de vaches infectées interfère pour atténuer la prolifération cellulaire. II semble qu’un constituant du sérum provoque une diminution de la réponse immunitaire chez les vaches malades. Les résultats offrnt une appréciation des dérèglements immunitaires provoqués par la paratuberculose bovine.

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 152-176).

Made available in DSpace on 2015-07-22T20:50:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-08-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Mycobacterium avium e Mycobacterium kansasii são micobactérias não tuberculosas frequentemente isoladas em infecções em pacientes HIV positivos. Em um projeto anterior do laboratório foi estudado um cultivo misto de M. avium e M. kansasii isolado da medula óssea de um paciente HIV positivo. Estudando colônias isoladas deste cultivo, foi possível observar que a cepa de M. kansasii possuía a sequência de inserção IS1245, que é especifica de M. avium. A presença deste elemento de inserção em M. kansasii foi confirmada por PCR-IS1245, RFLP-IS1245 e sequenciamento. Este estudo teve como objetivo investigar o mecanismo de transferência da IS1245 para M. kansasii. Uma banda de aproximadamente 100 kb foi detectada por PFGE em colônias de M. avium e de M. kansasii deste cultivo misto. Testes de mobilidade desta banda de DNA em géis de PFGE, em diferentes condições de corrida, e testes com exonucleases e com topoisomerase I comprovaram que esta banda era um plasmídeo linear (pMA100), que continha proteínas covalentemente ligada nos seus terminais 5’. Estes achados levaram à hipótese de que o plasmídeo pMA100 seria responsável pela transferência natural do elemento IS1245 de M. avium para M. kansasii por conjugação. Experimentos in vitro reproduziram o evento de conjugação, tanto com a cepa de M. kansasii isolada do cultivo misto, como com outras duas cepas de M. kansasii não relacionadas. A sequência de inserção se manteve estável no genoma de M. kansasii após 10 subcultivos e foi observada a ocorrência de transposição de modo replicativo em M. kansasii. Pela primeira vez está sendo demonstrada a transferência horizontal de genes natural entre espécies diferentes de micobactérias. / 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. / TEDE / BV UNIFESP: Teses e dissertações

Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2015-11-16T16:31:34Z No. of bitstreams: 1 texto completo.pdf: 1375656 bytes, checksum: 6b33bdf6230c90a2e18e46517b201f11 (MD5) / Made available in DSpace on 2015-11-16T16:31:34Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1375656 bytes, checksum: 6b33bdf6230c90a2e18e46517b201f11 (MD5) Previous issue date: 2015-06-03 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Minas Gerais é o principal produtor de leite de cabra na região Sudeste e o terceiro principal estado do país nessa atividade. A paratuberculose é uma enfermidade intestinal crônica, causada por Mycobacterium avium subsp. paratuberculosis (Map), que acomete principalmente ruminantes e é transmitida pela ingestão de alimentos ou água contaminados por fezes de animais acometidos. O objetivo do trabalho foi identificar e caracterizar Mycobacterium avium subsp. paratuberculosis em fazendas de caprinos leiteiros da Zona da Mata de Minas Gerais. Foram estudadas dez propriedades, caracterizadas através da aplicação de um questionário com a pessoa responsável pelo manejo. Foram coletadas amostras de fezes e de leite dos 467 animais amostrados, que foram inoculadas em meio HEYM. As amostras de leite e as colônias suspeitas foram submetidas à PCR e aquelas consideradas positivas foram sequenciadas. Onze (2,36%) animais foram considerados positivos para a presença de Map, em quatro (40%) propriedades. Através das técnicas utilizadas, concluiu-se que Map está presente nas propriedades de caprinos leiteiros da Zona da Mata de Minas Gerais. Com esse estudo, foi possível analisar e caracterizar os diferentes modos de produção de leite de cabra empregados na Zona da Mata. Os produtores têm relativa instrução, mas ainda convivem com a baixa produtividade e o baixo rendimento da produção, o que leva a maioria a necessitar de outras fontes de renda. O incentivo governamental exerce papel fundamental na mudança do cenário atual da caprinocultura leiteira dessa mesorregião e, levando à estruturação da cadeia produtiva, alcança melhores resultados de produção e geração de emprego e renda no meio rural. / The participation of dairy goat in the Brazilian agricultural scenario has increased and has consolidated as profitable. Minas Gerais is the main producer of goat's milk in the Southeast and the third largest state in the country in this activity. The paratuberculosis is a chronic intestinal illness caused by Mycobacterium avium subsp. paratuberculosis (Map), which mainly affects ruminants and is transmitted by ingesting food or water contaminated by feces of affected animals. The objective was to identify and characterize Mycobacterium avium subsp. paratuberculosis in dairy goat farms in the Zona da Mata of Minas Gerais. Ten properties were studied, characterized by applying a questionnaire to the person responsible for the handling. Samples of feces and milk were collected of 467 animals studied, and inoculated in HEYM medium. Samples of milk and suspected colonies were submitted to PCR, and the samples considered positive were sequenced. Eleven (2.36%) animals were considered positive for the presence of Map, in four (40%) properties. Through the techniques used, it was concluded that Map is present in dairy goats properties of Zona da Mata of Minas Gerais. With this study, we analyzed and characterized different types of goat production used in the Zona da Mata. Producers have relative education, but still living with low productivity and low income of their production, which leads most in need of other sources of income. The government incentive plays a fundamental role in changing the current scenario of dairy goat at this region and, leading to the structuring of the production chain, achieves better results of production and generation of employment and income in rural areas.

Mycobacterium avium, an opportunistic human pathogen, infects between 25 and 50% of advanced-stage acquired immuno-deficiency syndrome (AIDS) patients in the United States. M. avium has been isolated from many environmental sources including: natural waters, soils, and aerosols. M. avium has also been recovered from within municipal and hospital drinking water systems. Rhesus macaques (Macaca mulatta) infected with the simian HIV analog, SIV, have been shown to acquire M. avium infections from potable water. Reduced-aggregate fractions (cell suspensions free of large aggregates) of Mycobacterium avium were exposed to chlorine, monochloramine, chlorine dioxide, and ozone and kinetics of disinfection measured. Chlorine disinfection kinetics was also measured in M. avium cultures grown in biofilms. M. avium exhibited a high resistance to chlorine compared to E. coli. M. avium CT99.9% (disinfectant concentration x time to 3 logs cell inactivation) values were between 571- and 2318 -times those of E. coli. Clinical isolates of M. avium showed 0.24 and 2.5-fold increase in resistance to chlorine compared to their pulsed-field-gel-electrophoresis- (PFGE) matched environmental isolates. M. avium strains exhibited a mixed response to exposure to monochloramine. The CT99.9% values of three strains (2 clinical, 1 environmental) were between 6.3- and 23.5- times that of E. coli. Two strains (1 clinical, 1 environmental) exhibited CT99.9% values approximately the same as E. coli, a difference from all the other disinfectants which were much less effective on M. avium than on E. coli. M. avium strains exhibited a high resistance to chlorine dioxide when compared to E.coli. M. avium CT99.9% values of between 133- and 706- times higher that that of E. coli. In the paired isolates tested, the clinical isolate was 5.3 times more resistant than the matched environmental isolate. M. avium exhibited a high resistance to ozone when compared to E. coli. M. avium strains exhibited a CT99.9% value of between 52 and 90 times higher that that of E. coli. In the paired isolates tested, the clinical isolate was nearly identical as judged by CT99.9% values. M. avium strain 5002 exhibited an unusual disinfection kinetics curve. Disinfection rate increased by a non-logarithmic factor, indicating that inactivation efficiency was increasing over time. M. avium strain 1060 showed between a 17% decrease to a 265% increase in CT99.9% value when grown as biofilms as opposed to suspension. Due to the large variance in biofilm density and and CT99.9% values, any conclusions based on these experiments should be considered tentative at best. M. avium's resistance to chlorine and chlorine dioxide approaches that of the protozoan cysts of Giardia muris and Entamoeba hystolytica. M. avium is much less resistant, relatively, to monochloramine possessing values similar to E. coli. Ozone resistance of M. avium is two orders of magnitude greater than E. coli and one order of magnitude of less than G. muris cysts. A critical concentration threshold level for chlorine dioxide was found. That is, there was no linear relationship between concentration of chlorine dioxide and cell inactivation. Initial experiments using a range of concentrations from 0.1 ppm to 0.5 ppm chlorine dioxide showed a biphasic curve with the inflection point (indicating the critical concentration) between 0.3 and 0.4 ppm chlorine dioxide. / Master of Science

Mycobacterium avium is human and animal opportunistic pathogen responsible for disseminated disease in immunocompromised patients. Mycobacteria have a capacity to adapt to the environmental conditions by inducing enzyme activities and altering their metabolism. M. avium A5 cells were grown in a defined minimal medium (Nitrogen Test Medium) with glutamine, nitrite, nitrate, or ammonia as sole nitrogen source at a concentration of 2 mM at 370C aerobically. The strain grew well on all the nitrogen sources except nitrite. It grew slowly on nitrite with a generation time of 6 days and cultures were not viable after 4 weeks of storage. These data confirm that M. avium can utilize a single nitrogen source in a defined minimal medium as documented by McCarthy (1987). M. avium genome has been sequenced and contains genes sharing sequence similarities to respiratory nitrate reductase and dissimilatory nitrite reductases. Because, M. avium can use nitrate or nitrite as sole nitrogen source for growth (McCarthy, 1987), it must have assimilatory nitrate- and nitrite-reductases. Nitrate- and nitrite-reductase activities of M. avium cells growing aerobically or undergoing anaerobic shift in the presence of ammonia, nitrate or ammonia and nitrate in combination were measured. M. avium produced nitrate- as well as nitrite-reductase activity. Nitrite- and nitrate-reductases used either NADH or NADPH as an electron donor. Nitrite reductase activity was greater than nitrate reductase activity. This observation supports the rapid reduction of nitrite and slow reduction of nitrate in M. avium as documented by McCarthy (1987) and explained why M. avium gives a negative result by the standard nitrate reductase test. In addition to assimilatory enzyme activity, M. avium A5 also produced dissimilatory nitrate- and nitrite-reductase activities. / Master of Science

Organisms of the <i>Mycobacterium avium</i> complex cause disseminated infections in 25 to 50 % of patients with AIDS. To assess the likelihood of exposure to M avium, we attempted to recover M. avium complex from environmental samples in geographical areas (Boston, Massachusetts; Hanover, New Hampshire; Helsinki, Finland; Nairobi, Kenya; and Kinsasha, Zaire) located near <i>M. avium</i> infected AIDS patients. Although <i>M. avium</i> was recovered from environmental samples at all sites, it was found more frequently in water supply systems in the United States and Finland (8/25, 32 %) compared to water supply samples from Africa (0/14, 0%). To determine if <i>M. avium</i> isolates recovered from the same geographical area as AIDS patients shared phenotypic and genetic characteristics with clinical AIDS <i>M. avium</i> isolates (recovered by collaborating laboratories), the ability to grow at 43°C, cadmium-and streptomycin-resistance, and the presence of plasmids were used as epidemiological markers. We found that environmental isolates in this study shared similar characteristics with the clinical AIDS <i>M. avium</i> isolates. Compared to developed countries, the prevalence of <i>M. avium</i> infections among AIDS patients in developing countries (i.e., Africa) is very low. To determine if <i>M. avium</i> was absent in the African environment, we attempted to recover the organisms from water and soil in Kampala, Uganda. <i>M. avium</i> was recovered from 43 % of environmental samples, and these isolates shared similar phenotypic and genetic characteristics with <i>M. avium</i> isolates from the United States. Cigararette smoking was identified as a possible risk factor for HIV infected individuals. M avium isolates were recovered from several brands of cigarettes, suggesting that cigarettes are a possible source of infection. / Master of Science

Proteins of the cytoplasmic membrane of Mycobacterium avium were investigated to identify those which were: (1)intrinsic or extrinsic, (2) attached to the cell wall, (3)surface accessible and (4) excreted. In addition sera containing anti-cytoplasmic membrane proteins were obtained and preliminary purification of the cytoplasmic membrane protein was attempted. The predominating cytoplasmic membrane protein of 31,000 daltons (MCMP) was found to be intrinsic, attached to the cell wall and possibly surface accessible. The MCMP was not excreted, even in media in which the MCMP is not found in the cytoplasmic membrane. Other cytoplasmic membrane proteins were also found to be intrinsic; a few were likely to be extrinsic based upon their separation from the membrane in sucrose gradients. Cytoplasmic membrane proteins of 66, 000, 115, 000 and 129 dalton were surface accessible as judged by I 125-Iodobead labeling. Antisera against the HCMP and other cytoplasmic membrane proteins was obtained and will be useful in further cytoplasmic membrane protein characterization. Acetone precipitation of a cytoplasmic membrane preparation was performed to partially purify the MCMP. The data from this study can be used for the development of serodiagnostic reagents for detecting mycobacterial infection. / Master of Science