Identificando o potencial de virulência de cepas humanas de escherichia albertii

• Ano de defesa: 2016
• Autor(a) principal: Lima, Mauricio Pereira de [UNIFESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo (UNIFESP)
• Palavras-chave em Português: Escherichia albertii
• Link de acesso: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=4240346; http://repositorio.unifesp.br/handle/11600/46770

Escherichia albertii comprises a new species within the genus and has been considered an emerging enteric pathogen. However, the identification of E. albertii by traditional methods is somewhat difficult, due to their biochemical characteristics. Although little is known about their potential virulence mechanisms, it is known that various E. albertii strains share some virulence factors with diarrheagenic pathotypes of E. coli (DEC). Although E. albertii genomes have been sequenced recently, little is known about their interaction with human epithelial cells, including enterocytes. Our group recently confirmed as E. albertii a set of five strains that were originally classified as atypical enteropathogenic E. coli (EPEC). However, a more detailed characterization of potential virulence mechanisms of these strains are required. In this study, phenotypic and virulence characteristics of five E. albertii strains isolated from children with diarrhea in São Paulo were analyzed. We evaluated the capacity to adhere to and to promote accumulation of actin filaments in HeLa cells (indicative of the ability to produce a characteristic lesion termed attaching/effacing, A/E), to invade and persist inside intestinal differentiated Caco-2 cells and to produce biofilm on abiotic surfaces. In addition, we investigated the profile of plasmid bands and the occurrence of virulence genes described in E. coli pathotypes associated with intestinal and extraintestinal infections. All strains adhered to and caused A/E lesion in vitro. Furthermore, three strains invaded intestinal Caco-2, although none of them persisted intracellularly for extended periods. Four strains formed biofilms on abiotic surfaces, which could be a factor in bacterial persistence, particularly in hospital environments. While the E. albertii strains have shown sensitivity to several antibiotics, and most of them were devoid of plasmids, one strain carrying self-transferable resistance plasmids was found. Among 33 and 16 genes of and extraintestinal pathogenic E. coli screened, six and four genes, respectively, were identified in different frequencies in these strains. Human strains of E. albertii have heterogeneous but significant virulence potential and may represent an emerging group of enteric pathogens in our environment. Additional studies on the epidemiology and mechanisms of virulence in vivo will provide a broader view of the pathogenenic potential of the species.