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| Author(s): |
Luisa Zanolli Moreno
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD) |
| Defense date: | 2017-04-20 |
| Examining board members: |
Andrea Micke Moreno;
André Furugen Cesar de Andrade;
Marcos Bryan Heinemann;
Terezinha Knöbl;
Eliana Scarcelli Pinheiro
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| Advisor: | Andrea Micke Moreno |
| Abstract | |
The present study aimed to characterize the genome of Leptospira strains isolated in Brazil and to perform their comparative analysis with GenBank available genomes. 17 strains isolated from distinct species, in different regions of Brazil, from 1998 to 2012 were characterized. These were previously typified through 16S rRNA sequencing and microscopic agglutination into six species (L. interrogans, L. santarosai, L. inadai, L. kirschneri, L. borgpetersenii and L. noguchii) and over eight serogroups. Illumina™ MiSeq sequencing and genome assembly with ab initio algorithm were performed. For ordering and annotation, reference genomes of the respective species were used. The in silico analysis of Multilocus Sequencing Typing (MLST) was performed for the three current Leptospira protocols. The comparative genomic analysis, including wgSNP, was performed intra-species evaluating the existing variations between the serogroups of the studied Leptospira species. The L. interrogans strains presented MLST results congruent with their previous identification. In the case of L. kirschneri, only one strain presented new alleles in the three MLST protocols and distanced itself from the other Brazilian L. kirschneri strains. The L. santarosai strains, as well as L. borgpetersenii and L. noguchii, presented new alleles and/or allelic profiles for at least two of the current MLST protocols, and still stand out in a separate group of Brazilian origin. Even though the L. interrogans genomes presented high identity and synteny with serovar Copenhageni reference, they also presented regions of difference between the respective serogroups. Serogroups Australis and Serjoe genomes stood out for having insertions and deletions, respectively, mainly in chromosome 2. The L. borgpetersenii genome also presented great variation of composition, as expected for the species, which is provided by insertion sequences and transposition of mobile elements. The serogroups Canicola and Pomona presented higher proximity in the wgSNP analysis. Two plasmids were also identified in the serogroup Canicola genomes with high identity to the plasmids described in the Chinese strain of the same serovar. In the L. kirschneri species, the strain 47 (M36/05) presented high identity and synteny with the serovar Mozdok genomes, as expected, including the Brazilian strain of human origin. The strain 55 (M110/06) differed from other L. kirschneri genomes in both MLST and wgSNP. The Brazilian L. inadai genome presented high identity to the American reference of human origin including the presence of bacteriophage specific for the species. The distinction of the Brazilian L. santarosai strains in the MLST was also evidenced in the comparative analysis and in the wgSNP, and the strain 68 (M52 / 8-19), which showed no reactivity to the tested serogroups, also differs from the others reaffirming the possibility of a new serogroup/serovar. Therefore, the genomic study allowed the identification of particularities of Brazilian Leptospira strains, including the existence of extrachromosomal elements, proximity to strains of human origin indicating a greater risk for public health, in addition to the possibility of a new L. santarosai serogroup. (AU) | |
| FAPESP's process: | 13/17136-2 - Characterization of Leptospira strains isolated in Brazil by pulsed field gel electrophoresis (PFGE) typing and comparative genomic analysis. |
| Grantee: | Luisa Zanolli Moreno |
| Support Opportunities: | Scholarships in Brazil - Doctorate |