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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.
1

Integrated study of group B streptococcus and human ureaplasmas � the paradigm shifts

Kong, Fanrong January 2004 (has links)
Group B streptococcus (GBS, S. agalactiae) and human ureaplasmas (U. parvumand U. urealyticum) are two clinically and phylogenetically related, potential perinatal pathogens. Their relationships between genotypes and pathogenesis of GBS and ureaplasma infection were still not well understood, one of the reason is that both of them are still short of a very practical genotyping system. In the study, to solve the above problem we developed genotyping systems for the organisms (the second section). For human ureaplasmas, based on four genes/gene clusters (rRNAgene clusters, the elongation factor Tu genes, urease gene complexes and multiplebanded antigen genes), we designed many primer pairs suitable for developing species identification assays for the two newly established human ureaplasma species (U. parvum and U. urealyticum). Further, based on the heterogeneity of ureaplasma multiple banded antigen gene (which contains species- and serovar-specific regions), we developed genotyping methods for each ureaplasma species.For GBS, based on three sets of molecular markers (capsular polysaccharidesynthesis gene clusters, surface protein antigen genes and mobile genetic elements),we developed a genotyping system. The primary evaluation of the genotyping systems showed that the genotyping systems were practical alternative assays for the conventional serotyping and they will be useful to further explore the relationships between genotypes and pathogenesis of GBS and ureaplasma infection. In the study, we introduced novel data and tools into GBS and ureaplasma studies especially from genomic- and bioinformatics-based molecular microbiology(the third section). For two newly established human ureaplasma species, based on the U. parvum serovar-3 genome, and using the above four important genes/geneclusters, we exposed some interesting problems in the understanding of newureaplasma taxonomy especially in the post genomic era. For GBS, we studied the two published full genomes and exposed some new problems or possible future new research fields. In particular we found the two finished and one ongoing GBS genomes were all non-typical and suggest that future genomic project had better have genetic population structure viewpoint. Finally, we suggested that integrated studies of the two potential or conditional perinatal pathogens, from the viewpoint of evolution, would provide a new understanding angle of the pathogenesis of the two organisms. Studies suggested that during coevolution, human ureaplasmas(especially U. parvum) became friendlier than their ancestors to their human host (by losing most of its virulence genes); however, GBS tried to increase its invasive abilities (by getting more virulence genes) to fight against the human host attack.
2

Integrated study of group B streptococcus and human ureaplasmas � the paradigm shifts

Kong, Fanrong January 2004 (has links)
Group B streptococcus (GBS, S. agalactiae) and human ureaplasmas (U. parvumand U. urealyticum) are two clinically and phylogenetically related, potential perinatal pathogens. Their relationships between genotypes and pathogenesis of GBS and ureaplasma infection were still not well understood, one of the reason is that both of them are still short of a very practical genotyping system. In the study, to solve the above problem we developed genotyping systems for the organisms (the second section). For human ureaplasmas, based on four genes/gene clusters (rRNAgene clusters, the elongation factor Tu genes, urease gene complexes and multiplebanded antigen genes), we designed many primer pairs suitable for developing species identification assays for the two newly established human ureaplasma species (U. parvum and U. urealyticum). Further, based on the heterogeneity of ureaplasma multiple banded antigen gene (which contains species- and serovar-specific regions), we developed genotyping methods for each ureaplasma species.For GBS, based on three sets of molecular markers (capsular polysaccharidesynthesis gene clusters, surface protein antigen genes and mobile genetic elements),we developed a genotyping system. The primary evaluation of the genotyping systems showed that the genotyping systems were practical alternative assays for the conventional serotyping and they will be useful to further explore the relationships between genotypes and pathogenesis of GBS and ureaplasma infection. In the study, we introduced novel data and tools into GBS and ureaplasma studies especially from genomic- and bioinformatics-based molecular microbiology(the third section). For two newly established human ureaplasma species, based on the U. parvum serovar-3 genome, and using the above four important genes/geneclusters, we exposed some interesting problems in the understanding of newureaplasma taxonomy especially in the post genomic era. For GBS, we studied the two published full genomes and exposed some new problems or possible future new research fields. In particular we found the two finished and one ongoing GBS genomes were all non-typical and suggest that future genomic project had better have genetic population structure viewpoint. Finally, we suggested that integrated studies of the two potential or conditional perinatal pathogens, from the viewpoint of evolution, would provide a new understanding angle of the pathogenesis of the two organisms. Studies suggested that during coevolution, human ureaplasmas(especially U. parvum) became friendlier than their ancestors to their human host (by losing most of its virulence genes); however, GBS tried to increase its invasive abilities (by getting more virulence genes) to fight against the human host attack.
3

Integrated study of group B streptococcus and human ureaplasmas : the paradigm shifts

Kong, Fanrong January 2004 (has links)
Group B streptococcus (GBS, S. agalactiae) and human ureaplasmas (U. parvumand U. urealyticum) are two clinically and phylogenetically related, potentialperinatal pathogens. Their relationships between genotypes and pathogenesis ofGBS and ureaplasma infection were still not well understood, one of the reason isthat both of them are still short of a very practical genotyping system. In the study,to solve the above problem we developed genotyping systems for the organisms (thesecond section). For human ureaplasmas, based on four genes/gene clusters (rRNAgene clusters, the elongation factor Tu genes, urease gene complexes and multiplebanded antigen genes), we designed many primer pairs suitable for developing species identification assays for the two newly established human ureaplasmaspecies (U. parvum and U. urealyticum). Further, based on the heterogeneity ofureaplasma multiple banded antigen gene (which contains species- and serovar-specific regions), we developed genotyping methods for each ureaplasma species.For GBS, based on three sets of molecular markers (capsular polysaccharidesynthesis gene clusters, surface protein antigen genes and mobile genetic elements),we developed a genotyping system. The primary evaluation of the genotypingsystems showed that the genotyping systems were practical alternative assays forthe conventional serotyping and they will be useful to further explore therelationships between genotypes and pathogenesis of GBS and ureaplasmainfection. In the study, we introduced novel data and tools into GBS and ureaplasmastudies especially from genomic- and bioinformatics-based molecular microbiology(the third section). For two newly established human ureaplasma species, based onthe U. parvum serovar-3 genome, and using the above four important genes/geneclusters, we exposed some interesting problems in the understanding of newureaplasma taxonomy especially in the post genomic era. For GBS, we studied thetwo published full genomes and exposed some new problems or possible future newresearch fields. In particular we found the two finished and one ongoing GBSgenomes were all non-typical and suggest that future genomic project had better have genetic population structure viewpoint. Finally, we suggested that integratedstudies of the two potential or conditional perinatal pathogens, from the viewpointof evolution, would provide a new understanding angle of the pathogenesis of thetwo organisms. Studies suggested that during coevolution, human ureaplasmas(especially U. parvum) became friendlier than their ancestors to their human host(by losing most of its virulence genes); however, GBS tried to increase its invasiveabilities (by getting more virulence genes) to fight against the human host attack.
4

Characterization of Phosphoglycerate Kinase Expressed on the Surface of Group B Streptococcus

Boone, Tyler J Unknown Date
No description available.
5

Integrated study of group B streptococcus and human ureaplasmas : the paradigm shifts

Kong, Fanrong January 2004 (has links)
Group B streptococcus (GBS, S. agalactiae) and human ureaplasmas (U. parvumand U. urealyticum) are two clinically and phylogenetically related, potentialperinatal pathogens. Their relationships between genotypes and pathogenesis ofGBS and ureaplasma infection were still not well understood, one of the reason isthat both of them are still short of a very practical genotyping system. In the study,to solve the above problem we developed genotyping systems for the organisms (thesecond section). For human ureaplasmas, based on four genes/gene clusters (rRNAgene clusters, the elongation factor Tu genes, urease gene complexes and multiplebanded antigen genes), we designed many primer pairs suitable for developing species identification assays for the two newly established human ureaplasmaspecies (U. parvum and U. urealyticum). Further, based on the heterogeneity ofureaplasma multiple banded antigen gene (which contains species- and serovar-specific regions), we developed genotyping methods for each ureaplasma species.For GBS, based on three sets of molecular markers (capsular polysaccharidesynthesis gene clusters, surface protein antigen genes and mobile genetic elements),we developed a genotyping system. The primary evaluation of the genotypingsystems showed that the genotyping systems were practical alternative assays forthe conventional serotyping and they will be useful to further explore therelationships between genotypes and pathogenesis of GBS and ureaplasmainfection. In the study, we introduced novel data and tools into GBS and ureaplasmastudies especially from genomic- and bioinformatics-based molecular microbiology(the third section). For two newly established human ureaplasma species, based onthe U. parvum serovar-3 genome, and using the above four important genes/geneclusters, we exposed some interesting problems in the understanding of newureaplasma taxonomy especially in the post genomic era. For GBS, we studied thetwo published full genomes and exposed some new problems or possible future newresearch fields. In particular we found the two finished and one ongoing GBSgenomes were all non-typical and suggest that future genomic project had better have genetic population structure viewpoint. Finally, we suggested that integratedstudies of the two potential or conditional perinatal pathogens, from the viewpointof evolution, would provide a new understanding angle of the pathogenesis of thetwo organisms. Studies suggested that during coevolution, human ureaplasmas(especially U. parvum) became friendlier than their ancestors to their human host(by losing most of its virulence genes); however, GBS tried to increase its invasiveabilities (by getting more virulence genes) to fight against the human host attack.
6

Relationship of Movements and Behaviors to Group A Streptococcus Infections in Elementary School Children

Murphy, Tanya K., Snider, Lisa A., Mutch, P. Jane, Harden, Elaine, Zaytoun, Annette, Edge, Paula J., Storch, Eric A., Yang, Mark C.K., Mann, Giselle, Goodman, Wayne K., Swedo, Susan E. 01 February 2007 (has links)
Background: Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcus (PANDAS) research is based on the hypothesis that infections trigger changes in behavior and movement in children. Methods: We enrolled 693 children (ages 3 to 12 years) into a systematic, longitudinal study. Data were collected monthly for 8 months (October-May) to determine point prevalence of Group A Streptococcal (GAS) infections, tics, behavior, and choreiform movements. Simultaneous throat cultures were obtained, and relational analyses were made between GAS and movement/observation ratings. Results: Combined behavior/GAS associations (concurrent with or 3 subsequent months to GAS) revealed a strong relationship, relative risk (RR) of 1.71 (p < .0001). Detailed analysis revealed that balance/swaying and non-tic grimacing were responsible for a significant proportion of this association (RR = 2.92, p < .0001). A strong seasonal pattern was found, with fall being more significant for GAS infections and observation ratings (p < .0001) compared with winter/spring. Children with repeated streptococcus (n = 64) showed higher rates of behavior and distal choreiform observations (p = .005). Conclusions: Motor/behavior changes were noted to occur in relationship to positive GAS culture with support that repeated GAS increases risk.
7

Bioinformatic insights into the biosynthesis of the Group B carbohydrate in Streptococcus agalactiae

Sutcliffe, I.C., Black, G.W., Harrington, Dean J. 01 May 2008 (has links)
No / Streptococcus agalactiae is a major human and animal pathogen, most notable as a cause of life-threatening disease in neonates. S. agalactiae is also called the Group B Streptococcus in reference to the diagnostically significant Lancefield Group B typing antigen. Although the structure of this complex carbohydrate antigen has been solved, little is known of its biosynthesis beyond the identification of a relevant locus in sequenced S. agalactiae genomes. Analysis of the sugar linkages present in the Group B carbohydrate (GBC) structure has allowed us to deduce the minimum enzymology required to complete its biosynthesis. Most of the enzymes required to complete this biosynthesis can be identified within the putative biosynthetic locus. Surprisingly, however, three crucial N-acetylglucosamine transferases and enzymes required for activated precursor synthesis are not apparently located in this locus. A model for GBC biosynthesis wherein the complete polymer is assembled at the cytoplasmic face of the plasma membrane before translocation to the cell surface is proposed. These analyses also suggest that GBC is the major teichoic acid-like polymer in the cell wall of S. agalactiae, whereas lipoteichoic acid is the dominant poly(glycerophosphate) antigen. Genomic analysis has allowed us to predict the pathway leading to the biosynthesis of GBC of S. agalactiae.
8

Colonização de pacientes grávidas por Streptococcus agalactiae em Taguatinga, Distrito Federal, Brasil / Colonisation by group B streptococcus in pregnant patients in Taguatinga, Federal District, Brazil

Siqueira, Fabio [UNESP] 27 January 2017 (has links)
Submitted by FÁBIO SIQUEIRA null (fabiosqr@gmail.com) on 2017-02-02T16:15:56Z No. of bitstreams: 1 Tese Fábio Siqueira.pdf: 5157545 bytes, checksum: e3110e94c65818e724da50cfc84cb635 (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-02-06T15:51:30Z (GMT) No. of bitstreams: 1 siqueira_f_dr_bot.pdf: 5157545 bytes, checksum: e3110e94c65818e724da50cfc84cb635 (MD5) / Made available in DSpace on 2017-02-06T15:51:30Z (GMT). No. of bitstreams: 1 siqueira_f_dr_bot.pdf: 5157545 bytes, checksum: e3110e94c65818e724da50cfc84cb635 (MD5) Previous issue date: 2017-01-27 / Fundação de Ensino e Pesquisa em Ciências da Saúde (FEPECS) / Objetivo: verificar a prevalência do estreptococo do grupo B em gestantes de Taguatinga, Distrito Federal, Brasil. Desenho: Estudo transversal. Local: Taguatinga (Região metropolitana de Brasília), Distrito Federal, Brasil. Introdução: o estreptococo do Grupo B é responsável por infecções graves em neonatos, resultante da transmissão vertical por gestantes colonizadas nas regiões anal, perineal ou vaginal. A identificação das pacientes colonizadas e uso de profilaxia intraparto podem reduzir o risco de infeção neonatal Métodos: Estudo transversal em pacientes gestantes entre a 35 e 37ª. semana de gravidez. Foi coletado material das pacientes para identificação laboratorial do Estreptococo do grupo B. Também foram coletados dados epidemiológicos das pacientes como peso, altura, índice da massa corporal, uso de antibióticos durante a gravidez, comorbidades durante a gravidez (diabetes, doenças hipertensivas, hipotireoidismo), gemelaridade, entre outras. Resultados: a amostra foi composta de 501 gestantes e a prevalência para o estreptococo do grupo B foi de 14%. A média de idade foi de 29 anos e o índice de massa corporal de 30,7. Durante a gravidez 204 pacientes tiveram algum tipo de infecção e 201 foram usaram antibióticos, 95 foram diagnosticadas com diabetes melito gestacional e 74 com alguma doença hipertensiva. Conclusão: a prevalência encontrada não difere do verificado por outros autores. Dentre os fatores estudados nenhum manifestou-se como fator de risco ou de proteção para a colonização materna para o estreptococo do grupo B. / Objective: To verify the prevalence of group B streptococcus (GBS) in pregnant women in Taguatinga, Federal District, Brazil. Design: Cross-sectional study. Setting: Taguatinga (metropolitan region of Brasilia), Federal District, Brazil. Sample: 501 pregnant women Methods: This cross-sectional study was conducted in pregnant women between the 35th and 37th week of pregnancy. Samples were collected from patients for laboratory identification of GBS. Epidemiological data were also collected from patients, including weight, height, body mass index, use of antibiotics during pregnancy, pathologies during pregnancy (diabetes, hypertensive disease, hypothyroidism), and twin pregnancy. Main outcome measures: Presence or absence of GBS in pregnant women. Results: The sample was composed of 501 pregnant women, and the prevalence of GBS was 14%. The average age was 29 years, and the average body mass index was 30.7. During pregnancy, 204 patients had some kind of infection, 201 of them have used antibiotics, 95 were diagnosed with gestational diabetes mellitus, and 74 were diagnosed with some kind of hypertensive disease. Conclusion: The prevalence found does not differ from that verified by other authors. None of the studied factors was a risk or protection factor for maternal GBS colonization. / FEPECS: 064.000.052/2012
9

Epidémiologie, pathogénie et prise en charge des infections à Streptococcus pyogenes touchant les enfants de Bruxelles et de Brasília

Smeesters, Pierre 18 December 2007 (has links)
Les Streptocoques Béta-hémolytiques du groupe A (GAS) sont responsables de manifestations cliniques variées et de séquelles non suppuratives comme notamment le rhumatisme articulaire aigu (RAA). Les affections sévères à GAS tuent plus de 500.000 personnes chaque année. Le pouvoir pathogène du GAS est encore mal compris. Il semble être notamment lié à la présence de nombreux gènes codant pour des facteurs de virulence dans le génome du GAS, dont celui codant la protéine emm. La protéine transmembranaire M joue un rôle essentiel dans la virulence du GAS. Le typage moléculaire des GAS se base sur la séquence de la partie hypervariable de ce gène (emm-typing). L’épidémiologie du GAS semble varier au cours du temps et en fonction de la localisation géographique et/ou du contexte socio-économique. Cependant, les différences dans les critères d’inclusion des différentes études épidémiologiques disponibles dans la littérature rendent les comparaisons difficiles. Pour mieux évaluer ces variations, nous avons mené une analyse prospective de l’épidémiologie clinique et moléculaire d’isolats de GAS provenant d’enfants présentant une infection à GAS, simultanément en deux localisations géographiques différentes (Bruxelles et Brasília, Brésil). Un des points importants de notre étude a été la mise en évidence de la diversité génétique de la protéine M des isolats belges et brésiliens. Alors que de nombreux emm-types différents sont retrouvés à Brasília (48 emm-types sur 128 isolats), ceux retrouvés à Bruxelles sont relativement peu nombreux (20 emm-types sur 200 isolats) et sont ceux communément retrouvés dans les pays industrialisés. Afin de mieux comprendre les bases moléculaires de cette différence, une analyse phylogénétique basée sur la quasi-totalité de la séquence de la protéine M exposée à la surface de la bactérie a été réalisée. Cette analyse a permis de montrer que les emm-types belges sont génétiquement éloignés les uns des autres alors que les emm-types brésiliens sont génétiquement plus proches. De manière intéressante, cette analyse a montré que les souches belges présentent une grande diversité au niveau de la région de la protéine M dite ‘constante’. En conséquence, la diversité génétique globale des protéines M belges et brésiliennes est similaire, mais elle se situe dans des régions différentes de la protéine M, ce qui pourrait indiquer l’existence de pressions de sélection différentes entre les deux pays. D’un point de vue vaccinal, ces résultats indiquent qu’un vaccin dirigé contre certaines des parties constantes de M présenterait une bonne couverture théorique dans les deux pays. Par contre, le vaccin 26-valent, en cours d’évaluation clinique, aurait une couverture théorique de 76% à Bruxelles et de 32% à Brasília. Notre analyse phylogénétique a également permis de montrer que la non-sensibilité à la ciprofloxacine (observée dans 22,5 % et 9% des souches belges et brésiliennes respectivement) survient dans des souches génétiquement éloignées, contrairement à ce qui est proposé actuellement dans la littérature. De plus, nous avons mis en évidence un polymorphisme au sein des gènes codant les topoisomérases cibles de la ciprofloxacine. L’identification de mutations responsables du phénotype de non-sensibilité nécessite par conséquent une confirmation expérimentale. Les manifestations cliniques sont assez différentes entre Bruxelles et Brasília. Les infections cutanées sont beaucoup plus fréquentes à Brasília. De manière intéressante au Brésil, des souches de GAS présentant un tropisme cutané sont isolées du pharynx. Ces souches ‘cutanées’ pourraient avoir acquis des déterminants génétiques leur permettant de se développer dans des tissus pharyngés. De plus, ces résultats pourraient remettre en question le postulat que seules les souches de tropisme pharyngé sont impliquées dans le développement du RAA. D’autres études épidémiologiques dans des pays où le RAA est endémique devront être réalisées afin de préciser nos résultats et de mieux comprendre les mécanismes moléculaires menant au développement du RAA. Cependant, étant donné la prévalence du RAA et l’accès limité au diagnostic microbiologique des pharyngites dans le réseau public de soins au Brésil, nous avons développé un score clinique permettant de limiter les traitements antibiotiques chez les enfants probablement atteints de pharyngites virales. L’utilisation de ce score permettrait de réduire le nombre de prescriptions antibiotiques dans les pharyngites de l’enfant de 41 à 55% à Brasília. Le choc toxi-infectieux est une pathologie relativement rare et le RAA n’est quasi plus décrit dans les pays développés. Cependant, deux nourrissons ont présenté un choc toxi-infectieux suivi d’un RAA (HUDERF, Bruxelles). A notre connaissance, cette association clinique n’a jamais été décrite. L’analyse de ces deux cas du point de vue de la virulence bactérienne a révélé la présence de nombreux gènes de facteurs de virulence, portés par des phages et différents dans les deux souches. Nos résultats illustrent la complexité de la relation hôte-pathogène. La capacité des bactéries à s’adapter à leurs hôtes et à causer des pathologies dépend de nombreux facteurs, qui varient d’un isolat à l’autre, et dont l’importance varie d’un hôte à l’autre. Notre travail a permis d’exemplifier la diversité génétique des GAS, aussi bien au niveau du gène emm qu’au niveau des facteurs de virulence, et de l’implication de ceux-ci dans le développement de pathologies streptococciques rares.
10

Colonização de pacientes grávidas por Streptococcus agalactiae em Taguatinga, Distrito Federal, Brasil

Siqueira, Fabio. January 2017 (has links)
Orientador: Adriano Dias / Resumo: Objetivo: verificar a prevalência do estreptococo do grupo B em gestantes de Taguatinga, Distrito Federal, Brasil. Desenho: Estudo transversal. Local: Taguatinga (Região metropolitana de Brasília), Distrito Federal, Brasil. Introdução: o estreptococo do Grupo B é responsável por infecções graves em neonatos, resultante da transmissão vertical por gestantes colonizadas nas regiões anal, perineal ou vaginal. A identificação das pacientes colonizadas e uso de profilaxia intraparto podem reduzir o risco de infeção neonatal Métodos: Estudo transversal em pacientes gestantes entre a 35 e 37ª. semana de gravidez. Foi coletado material das pacientes para identificação laboratorial do Estreptococo do grupo B. Também foram coletados dados epidemiológicos das pacientes como peso, altura, índice da massa corporal, uso de antibióticos durante a gravidez, comorbidades durante a gravidez (diabetes, doenças hipertensivas, hipotireoidismo), gemelaridade, entre outras. Resultados: a amostra foi composta de 501 gestantes e a prevalência para o estreptococo do grupo B foi de 14%. A média de idade foi de 29 anos e o índice de massa corporal de 30,7. Durante a gravidez 204 pacientes tiveram algum tipo de infecção e 201 foram usaram antibióticos, 95 foram diagnosticadas com diabetes melito gestacional e 74 com alguma doença hipertensiva. Conclusão: a prevalência encontrada não difere do verificado por outros autores. Dentre os fatores estudados nenhum manifestou-se como fator de risco ou de proteçã... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

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