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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Caracterização fenotípica e genotípica de amostras de Salmonella spp. isoladas de suínos / Phenotypic and genotypic characterization of Salmonella spp. strains isolated from pigs

Zucon, Luciane Tieko Shinya 27 June 2008 (has links)
Entre os microrganismos relevantes para a segurança alimentar, bactérias do gênero Salmonella tem se destacado como causadoras de toxinfecções, sendo motivo de preocupação constante para a cadeia de produção de aves e suínos. Os objetivos deste trabalho foram estudar a ocorrência de Salmonella spp. em suínos sadios ao abate e em animais apresentando sinais clínicos de salmonelose, tipificação dos isolados através da sorotipagem, polimorfismo do comprimento de fragmentos amplificados (AFLP) e eletroforese em gel de campo pulsado (PFGE). Foram examinados 50 animais com sintomatologia sugestiva de salmonelose de 12 granjas dos Estados de São Paulo, Paraná e Rio Grande do Sul e analisadas amostras de fezes, linfonodos e suabes de carcaças de 124 animais de quatro frigoríficos do Estado de São Paulo. Dos suínos com sintomatologia clínica, 38% dos animais foram positivos para o isolamento de Salmonella spp., sendo selecionadas 45 cepas, classificadas como S.Typhimurium (29/45), S. Choleraesuis (9/45), S. Infantis (3/45) e S. enterica subsp. enterica (4/45). Dos 124 suínos sadios, 16,12% foram positivos para o agente, sendo isoladas 39 cepas que foram classificadas como S. London (11/39), S. Anatum (11/39), S. Typhimurium (8/39), S. Agona (2/39), S. Enteritidis (2/39) e S. enterica subsp. enterica (5/39). Através do AFLP, a caracterização genética dos isolados revelou índice discriminatório igual a 0,85 e gerou 12 perfis distintos. O índice discriminatório do PFGE foi 0,96 apresentando 31 padrões distintos. Ambas as técnicas possibilitaram uma boa correlação entre isolados, seus sorotipos e locais de isolamento, sugerindo grande potencial para sua aplicação na genotipagem de Salmonella spp. / Among relevant microorganisms to food security, Salmonella has been highlighted as a major cause of food borne diseases, being a constant concern for poultry and pig production chain. The goal of this study was to investigate the Salmonella spp incidence in healthy pigs at slaughter, as well as in pigs showing salmonellosis clinical signs, characterize strains by serotyping, Amplified fragment length polymorphism (AFLP) and Pulsed field gel electrophoresis (PFGE). Fifty animals, presenting salmonelosis suggestive clinical symptoms, from 12 swine herds from Sao Paulo, Parana and Rio Grande do Sul states were examined and clinical materials such as stool samples, lymph nodes and carcass swab from 124 animals from four Slaughterhouses in Sao Paulo state were analyzed. Among the pigs with clinical symptoms, 38% of the animals were positive for the Salmonella spp. isolation. Forty five strains were selected and classified as S.Typhimurium (29/45), S. Choleraesuis (9/45), S. Infantis (3/45) and S. enterica subsp. enterica (4/45). From the 124 healthy pigs studied, 16.12% were positive for the agent. Thirty nine strains were isolated and classified, by serotyping, as S. London (11/39), S. Anatum (11/39), S. Typhimurium (8/39), S. Agona (2/39), S. Enteritidis (2/39) and S. enterica subsp. enterica (5/39). Through AFLP, genetic characterization of isolates showed discriminatory index of 0.85 and generated 12 distinct profiles. The PFGE discriminatory index was 0.96, showing 31 distinct patterns. Both techniques allowed a good correlation between the isolates, its serotypes and isolation locations, suggesting great potential of its application in genotyping of Salmonella spp.
12

Caracterização genotípica de cepas de Haemophilus parasuis / Genotype characterization of Haemophilus parasuis strains

Castilla, Karina Salvagni 17 December 2008 (has links)
Haemophilus parasuis é um dos agentes bacterianos que tem assumido grande importância na indústria suinícola nos últimos anos. Por muitos anos foi considerada uma doença esporádica de suínos jovens, no entanto, com o surgimento de doenças imunossupressoras ou com o aumento da criação de suínos com alto status sanitário, sua freqüência vem assumindo proporções cada vez maiores. A caracterização das cepas através de métodos fenotípicos como a sorotipagem não tem sido suficiente para os estudos epidemiológicos sobre esta bactéria, uma vez que muitos isolados não são sorotipificáveis. Os objetivos deste estudo foram caracterizar os isolados através da sorotipagem, do Polimorfismo do Comprimento de Fragmentos Amplificados (AFLP) e da Eletroforese em Gel de Campo Pulsado (PFGE), comparando os resultados obtidos. Dentre as 51 cepas de Haemophilus parasuis avaliadas uma foi classificada como sorotipo 2, doze como sorotipo 4, seis como sorotipo 5, quatro como 13 e sete como sorotipo 14, sendo que vinte e uma amostras não foram sorotipificáveis. Através do AFLP foi possível caracterizar todos os isolados, com um índice discriminatório de 0,98, porém esta técnica não demonstrou uma boa reprodutibilidade. Através da PFGE utilizando a enzima Sma I apenas 14 cepas foram genotipadas, porém com a enzima Not I, todas apresentaram padrões de bandas e o índice discriminatório obtido foi de 0,95. Os perfis obtidos através da PFGE com a enzima Not I apresentaram a melhor correlação com os dados de origem das cepas e seus sorotipos, indicando que a técnica possui um bom potencial para aplicação em estudos epidemiológicos. / In recent years, Haemophilus parasuis has had a growing impact on the swine industry. In the past, Haemophilus parasuis infections were considered to be sporadic in young pigs. However, the incidence is increasing due to immunosuppressive diseases and the increase in the production of pigs with high sanitary status. Characterization of strains using methods based on phenotype identification is not enough to perform epidemiological studies on thebacterium, since a large percentage of isolates are nontypeable). The aim of this study was to characterize isolates according to serotyping, Amplified Fragment Length Polymorphism (AFLP), and Pulsed Field Gel Electrophoresis (PFGE), and to compare characterization results. Out of the 51 strains of Haemophilus parasuis evaluated in this study: one was serotype 2; twelve serotype 4; six serotype 5; four serotype 13; and seven serotype 14. Serotyping could not be performed on the remaining 21 samples. All isolates were characterized using AFLP, with a discriminatory index of 0.98, but reproducibility of this technique is not good. Regarding PFGE, 14 strains were genotyped using enzyme Sma I; yet, with enzyme Not I, all strains presented band size and discriminatory index power of 0.95. The profiles obtained using PFGE with Not I presented better correlation with the origin and serotype of the strains, suggesting that this technique could be used in epidemiological studies with promising results.
13

Caracterização fenotípica e genotípica de isolados de Actinobacillus pleuropneumoniae provenientes de diferentes estados brasileiros / Phenotypic and genotypic characterization of Actinobacillus pleuropneumoniae isolates from different Brazilian states

Bárbara Letícia Pereira Costa 11 April 2017 (has links)
A infecção por Actinobacillus pleuropneumoniae, doença conhecida como pleuropneumonia suína, assumiu grande importância na suinocultura moderna devido à alta ocorrência observada nos rebanhos. O impacto da doença está relacionado à capacidade do agente em causar pneumonia severa, levando os animais a óbito ou doença crônica, resultando em graves prejuízos zootécnicos. Diante desse cenário, o controle e monitoramento do agente se faz importante por meio da identificação dos diferentes sorotipos, da análise genética e da determinação dos perfis de resistência aos antimicrobianos. O objetivo do presente estudo foi caracterizar fenotípica e genotípicamente estirpes de Actinobacillus pleuropneumoniae isoladas a partir de quadros de pneumonia em suínos. Um total de 85 estipes de A. pleuropneumoniae foram submetidas a reação em cadeia pela polimerase (PCR) para identificação e sorotipagem, determinação da concentração inibitória mínima de antimicrobianos, polimorfismo do comprimento de fragmentos amplificados (AFLP) e eletroforese em gel de campo pulsado (PFGE). Os sorotipos mais frequentes foram: 5 (38,8%), 10 (29,4%), 7 (5,9%), 8 (5,9%) e 6 (3,5%), sendo que 14 (16,5%) estirpes foram não tipáveis. Foi observada alta heterogeneidade de perfil genético entre as estirpes analisadas, tanto pelo AFLP quanto pelo PFGE, e o índice discriminatório para cada técnica foi 0,97 e 0,84, respectivamente. Todas as estirpes foram sensíveis ao ceftiofur, gentamicina, tulatromicina e tilmicosina, sendo que 98,8% das estirpes foram resistentes à tilosina e altas taxas de resistência foram observadas ainda para as tetraciclinas, clindamicina e sulfadimetoxina. / Infection by Actinobacillus pleuropneumoniae, a disease known as swine pleuropneumonia, has gained greater relevance to modern pig farming due to the high recurrence rate observed in herds. The impact of the disease relates to the capacity of the agent to cause severe pneumonia, leading to animal death or chronic conditions, thus resulting in severe zootechnical losses. In view thereof, the control and monitoring of the agent is key, being performed through the identification of different serotypes, genetic analysis and determination of antimicrobial resistance profiles. The objective of this study was to characterize phenotypically and genotypically Actinobacillus pleuropneumoniae strains isolated from swine with clinical presentation of pneumonia. A total of 85 strains of A. pleuropneumoniae were subject to polymerase chain reaction (PCR) for identification and serotyping, determination of the minimal inhibitory concentration, amplified fragment length polymorphism (AFLP) and pulsed field gel electrophoresis typing techniques (PFGE). Most recurring serotypes were: 5 (38.8%), 10 (29.4%), 7 (5.9%), 8 (5.9%) and 6 (3.5%), of which 14 (16.5%) strains were nontypeable. High genetic heterogeneity was observed for both AFLP and PFGE, and the discriminatory index for each technique was 0.97 and 0.84, respectively. All 85 strains were susceptible to ceftiofur, gentamicin, tulatromicin and tilmicosin, 84 of which were resistant to tylosin, and high resistance rates were also observed for clindamycin, tetracyclines and sulfadimethoxine.
14

Optimisation of dengue diagnostic tools in order to increase the knowledge of the pathogenesis

Lindegren, Gunnel. January 2008 (has links)
Lic.-avh. (sammanfattning) Stockholm : Karolinska institutet, 2008.
15

Streptococcus pneumoniae : epidemiological, clinical and serological studies

Burman, Lars Å. January 1993 (has links)
A retrospective study of invasive pneumococcal disease in patients from Greater Göteborg in 1964- 1980 identified 125 cases of meningitis, 305 of pneumonia, 61 of septicemia with unknown focus, and 17 with other manifestations, all verified by cultures from normally sterile body fluids. The incidence was several times higher in infants and in the elderly than in any other age-group. A wide variety of underlying conditions were present in 23% of the infants, 34% of the children, and 81% of the adults. In adults alcoholism was known in one third of the cases. The case fatality rate was 24% among patients with underlying conditions and 9% among previously healthy individuals. The case fatality rate was 50% in patients with hospital-acquired infection. Twohundred-fifteen pneumococcal strains, isolated from blood or CSF from 1971 to 1983 at the laboratories of clinical bacteriology of Göteborg, Malmö, and Umeå were serotyped by coagglutination (COA). Of all isolates, 89% belonged to serotypes represented in the 23-valent vaccine. In a separate study COA was compared with counterimmunoelectrophoresis (CIE). COA was found to have several advantages; rapidity, lower cost, and ability to disclose serotypes with neutral charge, which constituted 19% of all strains. In a prospective study the etiology was determined in 196 hospitalized patients with pneumonia, most of them community-acquired. Culture of specimens from blood, transtracheal aspirate (TTA), sputum, and nasopharynx, assays of antigen in sputum, urine, and TTA, and assays of pneumococcal antibodies to capsular polysaccharide, C-polysaccharide, and pneumolysin in paired sera were performed. The etiology was established in 64% of the patients. Streptococcus pneumoniae was the most common agent (32%). In a serological study of patients with pneumococcal infection, diagnosed by culture of CSF, TTA, or blood, IgG antibodies against C-polysaccharide and pneumolysin were determined by ELISA. The diagnostic sensitivity was only 51% and 60%, respectively. In conclusion, invasive pneumococcal disease is strongly overrepresented at tender and high age and in patients with concomitant conditions, notably alcoholism. S. pneumoniae remains a predominant causative agent of community-acquired pneumonia in adults needing hospitalization. Due to the low sensitivity and/or specificity of individual microbiological techniques, a combined use of several techniques is necessary when trying to assess the relative importance of pneumococci and other agents in pneumonia. Extended use of the currently available pneumococcal vaccine and development of improved pneumococcal vaccines seem highly warranted. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1993, härtill 5 uppsatser.</p> / digitalisering@umu.se
16

Molecular epidemiology of pneumococcal carriage and invasive disease /

Sjöström, Karin, January 2007 (has links)
Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.
17

Microbial factors and host responses affecting severity of pneumococcal disease and pneumococcal carriage /

Sandgren, Andreas, January 2005 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2005. / Härtill 5 uppsatser.
18

Detection and epidemiologic subtyping of Legionella pneumophila using DNA-based molecular methods /

Bernander, Sverker, January 2003 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 7 uppsatser.
19

Hantaviruses : animal models, immunology and pathogenesis /

Klingström, Jonas, January 2004 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 6 uppsatser.
20

Streptococcus pyogenes infections and toxic shock syndrome : molecular epidemiology and immunotherapy /

Darenberg, Jessica, January 2006 (has links)
Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 4 uppsatser.

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