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| Author(s): |
Rafaella Fabiana Carneiro Pereira
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia |
| Defense date: | 2015-06-08 |
| Examining board members: |
Marcelo Lancellotti;
Marco Aurélio Ramirez Vinolo;
Carlos Emilio Levy;
Fabiani Gai Frantz;
Wilton Rogério Lustri
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| Advisor: | Luciana Maria de Hollanda; Marcelo Lancellotti |
| Abstract | |
Brazilian Purpuric Fever (BPF) is a fulminant pediatric disease characterized by conjunctivitis, fever, purpura and sepsis. The illness is caused by Haemophilus influenzae biotype aegyptius (Hae), a bacterium which was formerly associated with only self-limited purulent conjunctivitis. The virulence factors of Hae are not yet fully known. Therefore, this study proposes a better understanding of this pathogen. Nine strains of Hae, of which seven are associated with BPF, were compared for their genomes, expression of candidate genes for virulence and characterization of Hae's lipids in in vitro and in vivo infections assays. Hae associated with BPF presented genes that are absent in other Hae strains studied, such as crgA and hadA. Hae was not competent to transformation process and analysis of Hae genomes revealed the absence of genes related to competence in Haemophilus, which could explain the inability to genetically manipulate this bacterium. hadA e tabA genes showed distinct profiles of expression in Hae in hosts in vitro and in vivo, therefore it was not possible to infer their role in Hae¿s virulence. While las gene seems to be modulated negatively after interation with the host. Only Hae strains associated with BPF were recovered from infected Sprague-Dawley rats, suggesting that these strains acquired specific virulence determinants which assist in survival in the host. Mass spectrometry data of total lipids suggest that Hae suffers modifications after passing through the animal model. The findings showed that the strains analyzed associated with BPF not exhibit clonal characteristic, despite the similarities in their genomes. These strains have specific virulence factors possibly correlated with the occurrence of BPF and are promising candidates for future studies on the disease (AU) | |
| FAPESP's process: | 11/01319-5 - Study of the genome and virulence of Haemophilus influenzae biotype aegyptius associated with Brazilian Purpuric Fever |
| Grantee: | Rafaella Fabiana Carneiro Pereira |
| Support Opportunities: | Scholarships in Brazil - Doctorate |