Genômica comparativa de isolados resistentes à meticilina de Staphylococcus aureus pertecentes à linhagem ST239-SCCmecIII do clone epidêmico brasileiro

• Autor(a) principal: Costa, Maiana de Oliveira Cerqueira e
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações do LNCC
• Texto Completo: https://tede.lncc.br/handle/tede/278
• topic: Bioinformática; Genômica comparativa; Comparative genomics; Bioinformatics; CNPQ::CIENCIAS EXATAS E DA TERRA::CIENCIA DA COMPUTACAO::TEORIA DA COMPUTACAO::COMPUTABILIDADE E MODELOS DE COMPUTACAO; CNPQ::CIENCIAS BIOLOGICAS::GENETICA

The pathogen Staphylococcus aureus is a Gram-positive bacterium responsible for various infections acquired both in hospital and on the community. The emergence of isolate resistants to diferent antimicrobials such as MRSA (Meticillin-Resistant S. aureus) is a global concern to public health. In spite of the genomicconservation between S. aureus isolates, about 15% of it consists of regions of genomic plasticity (RGPs) and epidemic clones frequently carry a speci c repertoire of pathogenesis-related factors. The main goal of this work consists on using a comparative genomics approach, to characterize the MRSA isolates, obtained from Brazilian hospitals, belonging to the Brazilian Epidemic Clone (BEC) of the ST239-SCCmecIII lineage, and employing bioinformatics tools to compare them with publicly available S. aureus genomes of interest. The comparison of the chromosomal architecture reveals a great plasticity, speci cally in the Brazilian isolates, where GV69 presented several genomic rearrangements with large segments associated with inversions and translocations, that can be explained by the greater abundance of transposases in the genome of the same (80 classi ed genes). We identi ed 12 regions of genomic plasticity (RGPs) on one of the isolates but absent or variably conserved on the others. These regions shows evidence of horizontal gene transfer (HGT) such as the presence of transposases and phage elements. Moreover, a small plasmid was identi ed as part of the genome of BEC isolate BMB9393 which confers resistance to antimicrobial chloramphenicol. A large set of adhesins, genes involved in the acquisition of iron such as siderophores biosynthesis and resistance determinants were identi ed in the genomes of S. aureus belonging to the ST239 lineage, corroborating the hypothesis that the presence of virulence genes is lineage-speci c. This study and its underlying comparative genomics approach represents the rst focusing on the resistance and virulence gene repertoire of complete genomes belonging to BEC representatives isolated in Latin America. And the results obtained demonstrated a great arsenal of pathogenicity determinants in the Brazilian isolates that were responsible for epidemic spreads in local hospitals.