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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.
61

The study of candidate sialometabolism genes and sialometabolism gene regulation in Haemophilus influenzae

Tsai, Chen Hsuan Sherry January 2013 (has links)
Sialic acid (SA) is a known major virulence factor of Haemophilus influenza (Hi). This study aims to analyse the functions of some candidate sialometabolism genes, and to further our current understanding on the Hi sialometabolism gene regulation. Two candidate sialometabolism genes (HI0227 and HI0148) and their adjacent ORFs (HI0228, HI0148.1 and HI0149) were studied. HI0148.1 and HI0149 are transcribed as a single gene in screened NTHi strains, and we refer to the combined ORF as NTHI0236 (the designation in strain 86-028NP). Across Hi strains screened, the sequences of HI0227, HI0148 and NTHI0236 are conserved. However, the sequence of HI0228 is heterogeneous. Mutants that lack the functions of HI0227, HI0228, HI0148 and NTHI0236 were compared to their respective wild type parent strains for ability to grow on SA (in aerobic and microaerophilic conditions), their ability to sialylate LPS and their ability to resist complement mediated killing. The mutants did not exhibit major differences in the tested aspects of sialometabolism compared to their respective wild type strains. Changes observed in some of the mutants in serum bactericidal assays and LPS profiles were due to the effect of phase variable genes. The sialometabolism functions of HI0227, HI0148, and NTHI0236 remain obscure, and we postulate that HI0228 is a pseudogene. Investigation of Hi sialometabolism gene regulation was conducted using mutants that lack different steps of the Neu5Ac catabolism pathway and the Neu5Ac activation pathway. The expression of nanE and siaP, respectively representing the Neu5Ac catabolism and transport operons, were assessed using RT-PCR and qPCR. We investigated a temporal/concentration effect of Neu5Ac on the expression of sialometabolism operons, which highlights the importance of studying the Hi sialometabolism gene regulation as a dynamic process. We further demonstrated that GlcN-6P, a Neu5Ac intermediate from the catabolism pathway, is likely the SIS sugar that interacts with SiaR, the repressor protein of the Hi sialometabolism operons. We postulate that upon binding of GlcN-6P to SiaR, the SiaR-mediated repression on the Hi sialometabolism operons is relieved, resulting in the induction of the expression of Neu5Ac catabolism and transport genes.
62

Compréhension du métabolisme cellulaire et de la synthèse du polyoside capsulaire chez Haemophilus influenzae de type b / Understanding the cell metabolism and synthesis of the capsular polysaccharide from Haemophilus influenzae type b

Le hir, Jerome 25 October 2012 (has links)
Réalisé au sein du LISBP (Laboratoire d’Ingénierie des Systèmes Biologiques et des Procédés, INSA Toulouse), ce travail porte sur l’étude du germe pathogène Haemophilus influenzae de type b (Hib). L’objectif du travail est l’amélioration de la compréhension du métabolisme cellulaire et de la synthèse du polyoside capsulaire chez Hib, utilisé pour la fabrication du vaccin. Ainsi, une étude bibliographique associée à une analyse in silico et à une démarche expérimentale rationnelle a permis de développer un milieu chimiquement défini répondant aux critères de robustesse du procédé et de qualité du produit. Par ce travail, il a pu être défini les facteurs nutritionnels et environnementaux influents sur la production de biomasse et de PRP. Plus généralement, ce travail a permis une meilleure compréhension de la physiologie cellulaire. Une étude Bioinformatique et Transcriptomique a permis l’établissement de cartes métaboliques spécifiques de la souche Hib de notre étude, et de mieux comprendre l’influence du milieu de culture sur la production de polyoside capsulaire. En complément, une étude Fluxomique a permis de développer les connaissances sur le métabolisme général de la souche et plus particulièrement sur la voie de synthèse du polyoside.Sur un plan plus appliqué, une corrélation directe entre la consommation de glucose et la production de polyoside a pu être établie, et ce, dans un environnement maîtrisé de culture en fermenteur. La combinaison du travail développé tant sur le procédé que sur le milieu de culture chimiquement défini ou la sélection de souche, a permis, à l’échelle laboratoire, une multiplication par 6,2 de la production de polyoside capsulaire (7,8 en spécifique) par rapport à la condition initiale de l’étude en milieu complexe. Ce résultat a alors pu être validé chez Sanofi-pasteur à l’échelle pré-industrielle (1000L), tout en conservant une qualité du produit conforme aux critères de production pharmaceutique / This work, undertaken at LISBP (Laboratoire d’Ingénierie des Systèmes Biologiques et des Procédés, INSA Toulouse), concerns the study of the pathogen Haemophilus influenzae type b (Hib). The objective was to improve the understanding of cellular metabolism and the synthesis of the capsular polysaccharide in Hib, used for vaccine production. A literature review coupled with a rational experimental approach has enabled a chemically defined medium that meets the criteria of process robustness and product quality to be developed. This work has defined the key nutritional and environmental factors affecting biomass and PRP production. Bioinformatics and Transcriptomic studies have allowed the specific metabolic characteristics of the Hib strain to be mapped and enabled a better understanding of the influence of culture medium on capsular polysaccharide production to be obtained. A Fluxomics study points to specific organization of the central pathways and more specifically the interaction between the pentose phosphate pathway and the pathway of polysaccharide biosynthesis. On a more applied aspect, direct correlation between glucose consumption and production of polysaccharide was established in a batch culture. The combined knowledge obtained in this study enabled a 6.2-fold increase in production of capsular polysaccharide (7.8 in specific production) to be obtained in laboratory scale installations as compared to the initial fermentation process using complex media. This result was then validated at Sanofi-pasteur at the pilot-plant level (1000L), and shown to maintain product quality as defined by pharmaceutical production criteria
63

Conjugative transfer and phylogeny of an antibiotic resistant haemophilus element, ICEHin1056

Robinson, Esther Rhiannon January 2012 (has links)
Antibiotic resistance in bacteria is a growing threat to global health. Many of the genes responsible for resistance are carried on mobile genetic elements which can be transferred laterally between strains and species. The most important of these are conjugative and mobilisable elements including plasmids and integrating and conjugating elements, ICEs. Haemophi/us influenzae is an important human pathogen, which was first identified as carrying antibiotic resistance genes in the 1970s. Much of this resistance is encoded by ICEHin1056, which is present in H. influenzae strains worldwide. The aims of this study were to describe features of the biology of ICEHin1056, with particular reference to the genetic site and control mechanisms responsible for instigating conjugative transfer. The origin of transfer has been localised to a sequence on ICEHin1056 and an environmental stressor initiating conjugative transfer, oxidative stress, has been identified. In addition, detailed phylogenetic analysis has demonstrated ICEHin1056 to be part of a much larger family of mobile genetic elements, widely distributed in proteobacteria and carrying accessory genes responsible for survival in adverse environments, virulence and antibiotic resistance. The ICEs in the family have conserved homology of gene content and synteny of gene arrangement over deep evolutionary time, challenging the accepted paradigm of modular mosaicism of mobile genetic elements. A key event in increasing dissemination of the ICE, acquisition of a phage type integrase gene has also been identified. The findings presented provide significant insight into the behaviour of ICEs and may in future allow predictions about the spread of virulence factors and antibiotic resistance genes, with important implications for human and animal health.
64

Nontypeable Haemophilus influenzae outer membrane protein analysis, isolation, characterisation and vaccine potential

Webb, Dianne, n/a January 1998 (has links)
Heterogeneity in immunodominant outer membrane proteins has been proposed as a significant factor in the failure of an NTHi infection to induce immune protection against subsequent infections. This study has examined the vaccine potential of three outer membrane proteins in an attempt to identify conserved regions that could be targeted by an immune response after vaccination. The three proteins investigated were: TbpB, P5 and P48 (HI0164). The optimal route of immunisation in clearing a bolus inoculum of NTHi to the lung in the rat has been shown to be a combination of gut sensitisation with a respiratory boost and this regime was used in the present study. A panel of NTHi isolates was assessed to determine the frequency with which strains were able to bind transferrin and thus be targeted by a TbpBspecific immune response. A high proportion of strains was able to bind transferrin with similar frequencies in isolates associated with infection and those from normal throat swabs. A protocol was developed to purify nonlipidated recombinant TbpB from NTHi using a glutathione-Stransferase (GST)-rTbpB fusion protein and Glutathione-Sepharose affinity chromatography. Mucosal-directed immunisation with rTbpB significantly enhanced clearance of an NTHi challenge to the lung, however, whilst rTbpB-specific antibodies were cross-reactive on Western immunoblots, the cross-reactivity was variable in both transferrin binding inhibition assays and bactericidal activity. This suggested that the rTbpB-specific humoral response would be variable in the recognition of heterologous NTHi isolates. The secondary structure of P5 has been controversial with several reports suggesting that P5 was a fimbrin protein composed of coiled coils. In this present study the interstrain variation in P5 amongst isolates from diverse anatomical sites, as well as computer prediction methods and spectrophotometric analysis, generated a model of P5 based on the homologous E. coli protein, OmpA. This model suggested a B-barrel conformation with no evidence of coiled coils. Synthetic peptides corresponding to conserved regions of P5 that were thought to be surface exposed, as well as a region (H3) with some homology to a protective epitope in the P. aeruginosa protein, OprF, were then combined with a "promiscuous" T cell epitope from the measles virus F protein (MVF) and used for immunisation studies. Whilst variable protection was seen with the peptides, the MVF/H3 peptide was the most efficacious of the antigens assessed in this study in enhancing clearance of NTHi. This occurred in the absence of detectable peptide- or PS-specific antibody leading to the suggestion that cell mediated responses may have played an important role in enhancing clearance in this model. The highly conserved nature of the region in P5 represented by the H3 peptide suggests that further study should be focused on this peptide as a potential NTHi vaccine candidate. The last antigen, P48, is homologous to a A. pleuropneumoniae antigen, AopA, which has been proposed to have potential as a vaccine component against pleuropneumonia in pigs. Sequence analysis of the gene encoding P48 from several isolates showed that this protein was well conserved. Recombinant P48 was purified from a GST-rP48 fusion protein and used for immunisation, which also conferred significant protection. However, immunisation with rP48 was not as efficacious as immunisation with the MVF/H3 peptide. Whilst immunisation with rP48 induced high antibody titres, no bactericidal activity could be detected indicating that bactericidal antibody had not contributed to the observed clearance. In addition, the rP48- specific serum IgG was predominantly of the IgG2a isotype suggesting that Thl cell mediated responses had been induced by immunisation with rP48.
65

Immunomodulation in the context of developing a nontypeable Haemophilus influenzae vaccine

McGrath, John Francis, n/a January 2007 (has links)
One of the major challenges of vaccine development is the conservation of immunogenicity and protective efficacy through the stages of design, production, formulation and delivery. The critical issue is that how and in what form an antigen is taken up by antigen presenting cells for proteolytic processing and presentation to the immune system bound to MHC can have dramatic effects on the activation of Th cells to drive clonal responses and induction of immunological memory. Nontypeable Haemophilus influenzae (NTHi) is a pathogenic commensal of the human respiratory tract that causes diseases with enormous socioeoconomic burdens. There is no licensed vaccine, although the potential for vaccination with outer membrane components to reduce the incidence of disease caused by NTHi has recently been demonstrated in clinical trials. The issue of immunomodulation was explored in this thesis in the context of the further evaluation of a leading NTHi vaccine candidate, the outer membrane protein OMP26. The efficacy of recombinant OMP26 (rOMP26) against NTHi challenge has been previously demonstrated in mice, rats and chinchillas. In rats, efficacy was shown to be restricted to the precursor form (containing the signal peptide) and not the mature form of rOMP26. The immunodulatory effects of changes to the rOMP26 structure were further investigated in this thesis. A range of structural variants of rOMP26 were constructed in view of reducing extraneous plasmid-derived sequence from the antigen and to introduce a unique cysteine residue as a potential conjugate site for multivalent vaccine development (Chapter 2). It was demonstrated that minor structural changes to rOMP26 such as the addition, deletion, modification or relative positioning of a single amino acid or bulky group, designed to increase the efficiency of production or introduce (cysteine) conjugation sites, altered the expression of the protein in E. coli and the immunogenicity in Balb/C mice. Furthermore, in contradiction to the published report (El-Adhami et al. 1999) and a new study in rats (Chapter 3), there was no positive effect of the signal peptide in mice, with precursor and mature forms of rOMP26 equally immunogenic (Chapter 2). Following confirmation of the need to retain the signal peptide for the immunogenicity of rOMP26 in rats, a precursor form (rOMP26VTAL) in which the conserved n-region of the signal peptide was deleted, and shown to reduce the efficiency of the cleavage of the signal peptide by signal peptidase during protein overexpression in E. coli (Chapter 3). Not only did this deletion result in an increase the yield and stability of the purified precursor protein, but rOMP26VTAL was highly immunogenic and enhanced the clearance of NTHi from the lungs of challenged rats. The potential for signal peptides to be exploited as an immune-enhancing moiety in a proteinaceous vaccine is discussed. Following the development of rOMP26VTAL as a production optimised variant of rOMP26, the next step was to test the feasibility of rOMP26VTAL as a component of a multivalent vaccine (Chapter 4). Two chimeras were constructed with LB1(f)2,1,3, a trivalent synthetic B-cell epitope from the extracellular loop 3 region of the P5 fimbrin protein of NTHi, positioned at the N- or C-terminus of rOMP26VTAL. The solubility of rOMP26VTAL was affected by the fusion, with both chimera constructs expressed only in the insoluble fraction, thus requiring a denaturing protocol for purification. Although rLB1(f)2,1,3-OMP26VTAL was expressed and purified as a more stable protein and in greater yield than rOMP26VTAL-LB1(f)2,1,3, the relative positioning of the fusion was important and rOMP26VTAL-LB1(f)2,1,3 was significantly more immunogenic in rats than rLB1(f)2,1,3-OMP26VTAL. In addition, rOMP26VTALLB1( f)2,1,3, but not rLB1(f)2,1,3-OMP26VTAL induced a significant degree of bacterial clearance following pulmonary challenge with NTHi, in levels comparable to the highly efficacious rOMP26VTAL construct. In the third part of the thesis, bacterial ghosts were evaluated as a novel mucosal delivery technology for rOMP26VTAL and rOMP26VTAL-LB1(f)2,1,3, (Chapter 5). To mimic the natural presentation of OMP26 and P5 fimbrin antigens on the cell surface of NTHi, an OmpA� sandwich fusion surface display system was developed for the outer membrane expression of the OMP26 constructs in E. coli ghosts. Following gut immunisation, but not intranasal immunisation even when co-administered with the cholera toxin�derived adjuvant CTA1-DD, bacterial ghosts were successful at presenting OMP26VTAL and rOMP26VTAL-LB1(f)2,1,3 to the immune system for the induction of enhanced clearance of NTHi in the rat pulmonary challenge model. Although this study was the first to demonstrate enhanced bacterial clearance induced by heterologous antigens expressed in the outer membrane of bacterial ghosts, future studies with ghosts will require optimisation of the expression levels of the OmpA� fusion proteins possibly to avoid cross-reactive responses related to high doses of ghosts in the inoculum. This thesis presents data that both supports the further evaluation of rOMP26 constructs for clinical trials, and has demonstrated the significant effects of structural changes, method of production and delivery system can have on the immunogenicity of a candidate vaccine. Such knowledge will contribute to and provide some new approaches for enhancing the efficiency of vaccine development against a range of diseases including those caused by NTHi. Major Outcomes: 1. Demonstration that the immunogenicity of rOMP26 antigen constructs is affected by structural modifications and their positioning within the construct, and by the delivery system. 2. Development of rOMP26VTAL, an rOMP26 construct with the KNIAK sequence deletion of the signal peptide n-region. This protein retains the immunogenicity and protective efficacy of rOMP26, but is produced with reduced cleavage of the signal peptide, resulting in higher yields and a stable protein. Lacks extraneous plasmidderived multiple cloning site sequence, and is produced in high yield as a stable protein. 3. Construction of a NTHi rOMP26VTAL-LB1(f)2,1,3 chimera antigen that induced enhanced clearance of NTHi in an acute pulmonary challenge model in rats. 4. Development of an OmpA� surface display system for the expression of rOMP26 antigen constructs in the outer membrane of E. coli/bacterial ghosts 5. Bacterial ghosts were successful as delivery vehicles for rOMP26 candidate vaccine constructs when delivered in the gut.
66

Mechanisms of immunity to nontypeable Haemophilus influenzae in the lung

Foxwell, Alice Ruth, n/a January 1998 (has links)
Pulmonary infection caused by nontypeable Haemophilus influenzae (NTHi) is a significant cause of morbidity and mortality in both industrialised and developing countries. Previous work from this group resulted in the development of a respiratory model in rodents which has precipitated studies into the pathogenesis of infection by NTHi and investigation of the humoral and cellular mechanisms by which the bacteria are cleared from the lung. Comparison of mucosally immunised with non-immunised animals has demonstrated that not only are bacteria cleared more rapidly from the lungs, but there is a more rapid response and resolution of inflammatory factors in the mucosally immunised animals following challenge with NTHi. This inflammatory response is partially regulated by the ability of the mucosally immunised animals to rapidly produce, then control the production of tumour necrosis factor (TNF)-a. The TNF-a is produced by both macrophages and type I pneumocytes in the alveoli and also by the endothelial cells lining the blood vessels in the lungs. Immunocytochemical studies have identified cellular subsets accumulating in the lung at various time points following infection. Marked differences in cellular infiltration into the lung tissue were noted between immunised and non-immunised animals after challenge with NTHi. Immunised animals demonstrated an early influx of macrophages, CD8+ T cells and Y8+ T cells, followed by enhanced expression of the MHC-II marker, cellular infiltration by polymorphonuclear leukocytes and finally an increased number of both B cells and CD4+ T cells. In contrast, non-immunised animals did not demonstrate any proliferation nor extravasation of lymphocytes or increased expression of MHC-II before total bacterial clearance had occurred. Polymorphonuclear leukocyte infiltration occurred in the non-immunised animals, however at a later time than that seen in immunised animals. Challenging rodents to establish persistent infection highlighted the inappropriately aggressive white blood cell response to an initial challenge when bacteria may be masked by other substances, followed by the inability to amplify the polymorphonuclear leukocyte response on repeated challenge with NTHi. This hyporesponsiveness in the macrophage population, shown by lack of detectable TNF-a production, concomitant with low numbers of NTHi resulted in a continuously high number of macrophages in the alveoli and the possibility of increased damage to the lung tissue. The requirement for cell surface TNF-a and CD8+ T cells to enhance the clearance of NTHi from the lungs further strengthens previous in vitro and in vivo findings of the possible significance of cellular invasion as a mechanism of pathogenicity for NTHi. This thesis has contributed to the understanding of both the immune response to and the pathogenicity mechanisms of pulmonary infection with NTHi. Kinetic studies identifying cellular responses and cytokine levels have emphasised the ability of mucosal immunisation to increase the rate of immune response and resolution of inflammation to NTHi infection in the lung. Observations demonstrating a requirement for macrophages and CD8+ T cells in mechanisms associated with enhancing NTHi clearance from the lung will lead to further investigations.
67

Meningite por haemophilus influenzae em salvador, bahia: aspectos do período pré e pós vacinal

Lima, Josilene Borges Torres January 2007 (has links)
Submitted by Hiolanda Rêgo (hiolandarego@gmail.com) on 2016-07-29T17:20:06Z No. of bitstreams: 1 Tese_Med_Josilene Borges Torres Lima.pdf: 812403 bytes, checksum: f3a47d8a2a2a13648f9abf0ee0d4b9aa (MD5) / Approved for entry into archive by Delba Rosa (delba@ufba.br) on 2016-08-22T12:47:57Z (GMT) No. of bitstreams: 1 Tese_Med_Josilene Borges Torres Lima.pdf: 812403 bytes, checksum: f3a47d8a2a2a13648f9abf0ee0d4b9aa (MD5) / Made available in DSpace on 2016-08-22T12:47:57Z (GMT). No. of bitstreams: 1 Tese_Med_Josilene Borges Torres Lima.pdf: 812403 bytes, checksum: f3a47d8a2a2a13648f9abf0ee0d4b9aa (MD5) / A introdução de vacinas conjugadas contra o Haemophilus influenzae sorotipo “b” (Hib) foi um avanço de grande impacto na Saúde Pública, praticamente eliminando a meningite por Hib nos países onde foi implementada. O presente trabalho descreveu a meningite por H. influenzae em Salvador, Bahia, estudando o impacto da vacina, e caracterizou os isolados do sorotipo não “b”, identificados durante vigilância ativa populacional. A população estudada foi composta de pacientes identificados por cultura positiva para H. influenzae, e os dados clínicos obtidos através de entrevista e revisão de prontuário. O sorotipo dos isolados foi determinado utilizando antisoros, e reação em cadeia pela polimerase (PCR). A tipagem molecular foi realizada pelas técnicas de eletroforese em campo pulsátil e multilocus sequence typing; e para identificação de mecanismo de virulência, foi utilizada PCR e sequenciamento da região de deleção IS1016-bexA. Para cálculos de incidência foram utilizados números de casos da região Metropolitana de Salvador, e a população do censo do ano de 2000. Após 5 anos de introdução da vacina anti-Hib, a incidência da meningite pelo H. influenzae teve uma redução de 97,6% na população total, e de 97,5% em menores de cinco anos. Em 11 anos de vigilância, foram identificados 40 casos de meningite por isolados do sorotipo não b, sendo 80% após o uso da vacina. Na caracterização molecular, os isolados do sorotipo “a” foram agrupados em dois clones, sendo que um deles apresentava o fator de virulência, a deleção parcial IS1016-bexA, o qual foi associado com elevada mortalidade (OR 10,8 e IC 0,7-345). Estudos de epidemiologia molecular são importantes para estimar a eficácia da vacina, bem como monitorar a emergência de isolados de outros sorotipos para avaliar a necessidade de intervenção na composição da vacina.
68

Cepas de Haemophilus influenzae circulantes, antes e após a utilização da vacina contra o sorotipo b, e o contexto epidemiológico das doenças por Haemophilus no Brasil / Strains of Haemophilus influenzae before and after utilization of the vaccine Haemophilus b serotipes and epidemiologic context of diseases in Brazil

Almeida, Antonio Eugenio Castro Cardoso de January 2005 (has links)
Made available in DSpace on 2014-08-26T17:15:20Z (GMT). No. of bitstreams: 2 license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) 145.pdf: 1867505 bytes, checksum: 87dab03551d06be6de32b042de770c29 (MD5) Previous issue date: 2005 / Fundação Oswaldo Cruz. Instituto Nacional de Controle de Qualidade em Saúde / O presente estudo incluiu 235 cepas, procedentes dos estados de Santa Catarina (SC), Rio de Janeiro (RJ) e Pemambuco (PE). Verificamos que o Hib antes da vacinação predominava em mais de 90 por cento dos casos, sendo os outros tipos sorológicos raros. Após a vacinação, cai o tipo,b, crescem os tipos não b, em meningites, septicemias e infecções respiratórias. Os biotipos I e II foram os mais isolados. Houve variação da sensibilidade aos antimicrobianos testados (ampicilina, amoxicilina-ácido clavulânico, ceftriaxona, rifampicina, cloranfenicol e sulfametoxazol-trimetoprim), sobretudo na associação SMX- TMP cuja resistência dos Hi aumentou de 32,6 por cento para 65,8 por cento entre os dois períodos; enquanto se mantiveram taxas semelhantes de resistência para a ampicilina (17,5 por cento e 15,8 por cento) e a presença de cepas produtoras de p-lactamase; a sensibilidade à amoxicilina-ácido clavulânico e ceftriaxona foi de 100 por cento. Alteração na resistência ao cloranfenicol de 19,4 para 12,5 por cento e da rifampicina de 8,2 para 9,7 por cento.A tipagem sorológica realizada pelo método da SAL, teve bons resultados (96,2 por cento) e a molecular, pela PCR, diferenciou as cepas NT das capsuladas b -.Embora a estrutura populacional dos Hi tenha sido inicialmente descrita como clonal, os resultados obtidos através da técnica de ERIC- PCR, revelaram diversidade genética nas cepas estudadas. As do sorotipo b, revelaram 4 clones com diferentes características epidemiológicas. A diversidade genética foi maior nas Hinb e HiNT. Dos estados estudados, PE teve a mais alta diversidade genética (6 clones em 15 cepas) seguido do RJ (3 clones em 23 cepas) e SC (2 clones em 13 cepas). Concluímos, portanto, que há necessidade do monitoramento das cepas circulantes de Hi no país observando as possíveis alterações na prevalência dos sorotipos atuais e a real estimativa do impacto da vacina contra o Hib atualmente utilizada no Brasil. / The bacterial genus Haemophilus is included in the family Pasteurellaceae and the mostimportant specie causing infectious diseases in humans is the Hi. It shows capsularserotypes (a-f) as well as NT strains. A great number of different acute infectious diseasesare caused by this organism, especially affecting the CNS, as well as RD, occurringfrequently in children, especially with the Hib. Since 1988 disease associated with Hib hasbeen vaccine-preventable, by means of the first conjugate vaccine showing great efficacy.The vaccine is composed by the PRP and a carrier protein. However, the Hib is stillconsidered one of the most important human pathogens, which leaded us to developdifferent research lines, with isolates from different source of infections, after theintroduction of the conjugate vaccine against Hib by PNI/MS in 1999. We used in ourstudy 235 Hi isolates, from the brazilian states of Santa Catarina, Rio de Janeiro andPernambuco. Our results, show that the rate of type b infections before vaccination wasmore than 90%, whereas other serological types were rare. After the advent of the vaccine,we observe a decrease of type b and an increase of non-b isolation. Biotypes I and II arestill the most frequently isolated. The antimicrobial susceptibility found against ampicillin,amoxicillin-clavulanate, ceftriaxone, rifampicin, chloranphenicol and TMP-SMX, showed arecent increasing resistance against antibiotics commonly used to treat RD, especiallyamong the ones administrated by oral route, showing a resistance rate from 32.6% to 65.8%between the two periods studied. Ampicillin, showed resistance rates of 17.5% and 15.8%in the two periods studied and the presence of â-lactamase producing strains. Strainsevaluated against amoxicillin/clavulanate and ceftriaxone, were 100% sensible.Chloranphenicol showed a decrease in the resistance rates of the strains isolated during thepost-vaccination period, while rifampicin, showed an increase in the resistance rate from8.2 to 9.7%. The seroaglutination method used for capsular typing, showed good results,however, mutant b capsulated strains (b-), were only detected by the PCR, using specificprimers for the capsule region. The population structure of Hi which has been described asclonal, revealed a great genetic diversity by ERIC-PCR. Therefore we can conclude thatthere is a need of systematic tracking of circulating Hi strains in the country, continuouslywatching possible epidemiological changes and the evaluation of the impact of the vaccineagainst Hib used in Brazil to date.
69

Haemophilus influenzae: caracterização de cepas clínicas isoladas no município do Rio de Janeiro no período pós-vacinal (2000-2012) / Haemophilus influenzae: Characterization of clinical strains isolated in the city of Rio de Janeiro in the post-vaccination period (2000-2012)

Caldeira, Nathalia Gonçalves Santos January 2013 (has links)
Made available in DSpace on 2015-07-08T12:28:20Z (GMT). No. of bitstreams: 2 5.pdf: 1093384 bytes, checksum: 9432b61bcb4cfac37f05a1600b8f2fae (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2013 / Fundação Oswaldo Cruz. Instituto Nacional de Controle de Qualidade em Saúde / Haemophilus influenzae pode ser encontrado, normalmente, na microbiota do trato respiratório, do trato gênito-urinário e da cavidade oral. Porém, essa espécie inclui um dos mais importantes patógenos bacterianos em infecções principalmente pediátricas. As cepas de Hi podem ser capsuladas, variando de a-f, ou não capsuladas (não tipáveis - NT). O tipo capsular b foi o mais frequente em infecções graves infantis até a utilização da vacina conjugada contra Hib, sendo ainda considerado patogênico. No Brasil, essa vacina foi introduzida no Programa Nacional de Imunização do Ministério da Saúde em agosto de 1999, e como em outros países, promoveu uma acentuada diminuição em doenças causadas por esse agente. No entanto, estudos realizados na era pós-vacinal têm mostrado que a incidência de doenças invasivas causadas por H. influenzae não b e NT têm aumentado, inclusive no Brasil. O objetivo desse trabalho foi obter informações sobre as cepas de Hi circulantes no município do Rio de Janeiro. Utilizou-se 96 amostras de quadros infeciosos (46 invasivas e 50 não invasivas), isoladas no período pós-vacinal (2000-2012). Em relação à idade, dos 54 pacientes que tiveram esse dado, 32 tiveram doenças invasivas e 22 não invasivas. Em doenças invasivas, houve o predomínio de crianças < 5 anos. Enquanto que nas não invasivas os adultos > 70 anos predominaram. Entre as cepas obtidas, 15 foram capsuladas e 81 não capsuladas. A maioria das cepas capsuladas foi proveniente de sítios invasivos, cuja faixa etária predominante foi de < 5 anos. O tipo capsular mais isolado foi o b, seguido do a e f. As cepas Hib, predominaram no início do período de estudo, enquanto os outros sorotipos predominaram no final. No presente trabalho, não encontramos cepas mutantes deficientes de cápsula tanto Hib-, quanto Hia- / Haemophilus influenzae can be found usually in the microbiota of the respiratory tract, genitourinary tract and oral cavity. However, this species includes one of the most important bacterial pathogens mainly in pediatric infections. The strains can be capsulated Hi, (serotypes a-f), or not capsulated (nontypeable - NT). The type b capsular was the most frequent serious infection in children until the use of conjugate vaccine against Hib and is still considered pathogenic. In Brazil, this vaccine was introduced in the National Immunization Program of the Ministry of Health in August 1999, and as in other countries, promoted a significant decrease of disease caused by this agent. However, studies during the post-vaccine period have shown that the incidence of invasive disease caused by H. influenzae b and NT have increased, including in Brazil. The aim of this study was to obtain information on the Hi strains circulating in the municipality of Rio de Janeiro. We used 96 samples (46 invasive and 50 noninvasive), isolated during the post-vaccination period (2000-2012). Concerning the age of the 54 patients who had this data, 32 had invasive and 22 noninvasive disease. In invasive disease, there was a predominance of children <5 years. While in the noninvasive group, adults > 70 years predominated. Among the strains obtained, 15 were capsulated and 81 non-capsulated. Most capsulated strains originated from invasive sites whose predominant age group was <5 years. The most frequent capsular type was b, followed by a and f. Hib strains predominated at the beginning of the study period, while the other serotypes prevailed in the end. In this study, we did not found mutant strains deficient in both capsule Hib- and Hia-. NT strains accounted for the vast majority of isolates in this study, 32 strains isolated from invasive sites and 49 sites noninvasive, and were obtained from patients of all age groups. The capsulated strains were predominantly biotype I and II, while non-typeable strains were most II and III. In this study, only the NT strains were resistant to two drugs: ampicillin and trimethoprim - sulfamethoxazole. These were mostly non-invasive. Thus, none of the capsulated isolates were resistant. The PFGE patterns for the 96 strains were quite different, however eight NT strains belonged to the same genotype. Capsulated strains of the same serotype were similar, getting most isolates grouped in the same cluster. We therefore conclude that it is necessary to monitor the Hi strains circulating in Rio de Janeiro, because of the geographic and economic importance of this municipality. Such conduct should be extended to the whole country in order to understand the possible changes of serotypes today, which will certainly guide for the design of new vaccines, improvement of existing ones and the use of antibiotics, resulting in a public health impact.
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Asymptomatisches Trägertum von Staphylococcus aureus und Haemophilus influenzae bei Senioren / Asymptomatic carriage of Staphylococcus aureus and Haemophilus influenzae in elderly people

Drayß, Maria January 2022 (has links) (PDF)
Ältere Menschen sind gegenüber invasiven Infektionen und Sepsis besonders vulnerabel mit ungünstiger Prognose. Staphylococcus aureus und Haemophilus influenzae können beide invasive Infektionen verursachen. Oft geht eine asymptomatische Besiedelung einer Infektion voraus und ist ein Risikofaktor für eine invasive Infektion. Daher wurde eine bizentrische Querschnittstudie in den Regionen Aachen und Würzburg durchgeführt, um die Prävalenz von H. influenzae, S. aureus und MRSA (Methicillin resistenter S. aureus) bei asymptomatischen Senioren zu bestimmen, wie auch Risikofaktoren für eine Besiedelung. Von Oktober 2012 bis Mai 2013 wurden 677 Erwachsenen im Alter von 65 Jahren oder älter eingeschlossen, die zu Hause oder in Seniorenheimen lebten. Die Prävalenz von H. influenzae bei älteren Menschen war mit einer Trägerrate von nur 1,9% ([95% CI: 1,0 - 3,3%]; 13/677) sehr niedrig. Trägerisolate waren überwiegend nicht typisierbare H. influenzae, zeigten eine hohe clonale Diversität und waren alle Ampicillin-sensibel. Die Prävalenz von S. aureus war mit 28,5% ([95% CI: 25,1 - 32,1%]; 193/677) hoch, wie für die deutsche Allgemeinbevölkerung bekannt, während MRSA bei weniger als 1% der Teilnehmer gefunden wurde (0,7% [95% CI: 0,2 - 1,7%]; 5/677). Die Prävalenz von H. influenzae, S. aureus und MRSA unterschied sich nicht signifikant zwischen selbständig zu Hause lebenden Senioren und Pflegeheimbewohnern. Ältere, selbständig lebende Menschen mit höherem Bildungsniveau hatten signifikant höhere Kolonisierungsraten mit S. aureus (adjusted OR: 1,905 [95% CI: 1,248 - 2,908]; p = 0,003). Bei Pflegeheimbewohnern war eine Kolonisierung signifikant mit Verheiratet sein assoziiert (adjusted OR: 3,367 [95% CI: 1,502 - 7,546]; p = 0,003). Diese Ergebnisse unterstreichen die Bedeutung von sozio-demographischen Faktoren für eine Kolonisierung mit S. aureus und schließen eine Lücke bei epidemiologischen Daten zu H. influenzae. / Elderly people are especially vulnerable to invasive infections and sepsis with often poor outcome. Staphyloccus aureus and Haemophilus influenzae both can cause invasive infections. Asymptomatic colonization often precedes infection and poses a risk for invasive infection. Therefore, a bi-centric cross-sectional carrier study was conducted in the regions of Aachen and Wuerzburg, Germany, to determine the prevalence of H. influenzae, S. aureus and MRSA (methicillin resistant S. aureus) in asymptomatic elderly people and to identify risk factors for colonization. From October 2012 to May 2013 677 adults aged 65 years and older were included, living at home or in nursing homes. In contrast to children and younger adults the prevalence of H. influenzae was very low among elderly people with a carriage rate of only 1.9% ([95% CI: 1.0 - 3.3%]; 13/677). Carrier isolates were predominantly non typeable H. influenzae, showed a high clonal diversity and were all susceptible to ampicillin. The prevalence of S. aureus was expectedly high as known for the German general population (28.5% [95% CI: 25.1 - 32.1%]; 193/677), while MRSA was found in less than 1% of the individuals (0.7% [95% CI: 0.2 - 1.7%]; 5/677). The prevalence of H. influenzae, S. aureus und MRSA did not differ significantly between community dwellers and nursing home residents. Elderly community-dwellers with higher education level had significantly higher colonization rates with S. aureus (adjusted OR: 1.905 [95% CI: 1.248 - 2.908]; p = 0.003). Among nursing home residents, colonization was significantly associated with being married (adjusted OR: 3.367 [1.502 - 7.546]; p = 0.003). These results underline the importance of socio-demographic factors for colonization with S. aureus and close a gap in epidemiological data on H. influenzae.

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