Banca de QUALIFICAÇÃO: MATHEUS MIGUEL SOARES DE MEDEIROS LIMA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : MATHEUS MIGUEL SOARES DE MEDEIROS LIMA
DATE: 29/02/2024
TIME: 10:00
LOCAL: Google Meet, meet.google.com/jks-byue-kwf
TITLE:

Investigation of taxonomic discrepancies between E. casseliflavus genomes in public databases

KEY WORDS:

Enterococcus casseliflavus; Enterococcus flavescens; comparative genomics; genome based taxonomy

PAGES: 42
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

Enterococcus casseliflavus, a commonly mobile and yellow-colored bacterium, is a commensal member of the gastrointestinal tract. It is occasionally found in cases of bacteremia and other human infections. A concern is that all strains of this species have the VanC gene group on their chromosome, which confers resistance to vancomycin. The classification of E. casseliflavus is challenging, as it presents 99% identity in 16S analysis with E. gallinarum and, mainly, with E. flavescens, often being classified as a single species. This study aimed to develop a pipeline to investigate the phylogenetic relationship between E. casseliflavus and E. flavescens. An analysis pipeline was created that integrates measures of Average Nucleotide Identity (ANI), molecular phylogeny, and protein profile. 85 genomes of E. casseliflavus from NCBI were analyzed, comparing them with the reference genomes of E. casseliflavus and E. flavescens. The results indicated ANI differences greater than 5%, suggesting that E. flavescens should be considered a distinct species. In addition, a third clade of genomes was identified, possibly representing a new species of enterococci. The pangenome analysis revealed about 19 thousand genes, with 1154 core genes present in all species, indicating an open pangenome. The core gene phylogeny confirmed the division of the genomes into three groups, corroborated by the analysis of orthologous protein groups. The protein profile indicated possible events of horizontal gene transfer between the groups, with E. casseliflavus showing slightly more distant from the other two groups. The analysis of phylogenetic tree topologies revealed predominantly monophyly in the groups, but also horizontal gene transfer events. This study contributes significantly to the genomic and evolutionary understanding of E. casseliflavus and E. flavescens. It emphasizes the ongoing need for investigation to understand the differences in gene content and its functionality, as well as to identify genes associated with the speciation of these species. These findings have important implications for the diagnosis and management of infections related to vancomycin-resistant enterococci.

COMMITTEE MEMBERS:
Presidente - 3063244 - TETSU SAKAMOTO
Interna - 1149647 - LUCYMARA FASSARELLA AGNEZ LIMA
Externa à Instituição - FLÁVIA FIGUEIRA ABURJAILE - UFMG