Navegando por Palavras-chave "EPEC"

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    Caracterização molecular da formação de biofilme por Escherichia coli enteropatogênica (EPEC) O119
    (Universidade Federal de São Paulo (UNIFESP), 2019-02-28) Flores, Maricelia Navarro Pinheiro [UNIFESP]; Scaletsky, Isabel Cristina Affonso [UNIFESP]; http://lattes.cnpq.br/8411282118391609; http://lattes.cnpq.br/8538548568073264; Universidade Federal de São Paulo (UNIFESP)
    EPEC can be categorized into two subgroups, typical (tEPEC) and atypical (aEPEC), based on the presence or absence of the EPEC adherence factor plasmid (pEAF), respectively. EPEC colonizes the proximal small intestine, where it adheres to epithelial cells forming microcolonies. Microcolony formation is one of the initial steps in biofilm development, but, very little is known regarding biofilm formation by EPEC strains. Our laboratory investigated the ability of biofilm formation in a collection of 223 EPEC strains (70 typical and 153 atypical) belonged to EPEC and non-EPEC serogroups. Biofilm formation occurred in 11/ tEPEC and 37 aEPEC strains from different serotypes. Typical EPEC formed biofilm on a polystyrene plate at 37C, whereas aEPEC strains formed at 26C in LB, or LBNS. The gene sequences related to type 1 fimbriae, curli, flagellin, antigen 43, and the autotransporter proteins of enterohemorrhagic E. coli EhaA, EhaB (ehaBa and ehaBb) and Cah were identified in most of the typical and atypical biofilm-producing strains. The objetive of this study was to continue the studies of our laboratory, identifying the genetic determinant involved in the biofilm formation of one tEPEC strain. We began the study by selecting the tEPEC strain between the group of the strains previously characterized as biofilm forming. Biofilm formation quantification results showed that three strains presented strong biofilm and seven strains presented moderate biofilm at 37ºC in LBNS medium. Among the 3 strains, T29 (O119: H6) strain was selected for presenting a robust biofilm on abiotic surface and a dense pellicle at the air-liquid interface. The T29 strain (O119: H6) was mutagenized with the transposon mini-Tn10, and four mutants (M6, M21, M160 and M175) were identified that lost the ability to form biofilm on polystyrene surface and pellicle at the liquid-air interface. The DNA flanked by the transposon insert was cloned into the plasmid vector pUC19, and the clones obtained were sequenced. BLASTN analysis of the 529 bp and 322 bp sequences obtained from the sequencing of clones M6.1 and M21.1, respectively, revealed homology with the enzyme aspartate ammonia lyase and fimD gene related to fimbriae type 1. Studies are in progress with mutants M160 and M175.
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    Characterization of tccP2 carried by atypical enteropathogenic Escherichia coli
    (Blackwell Publishing, 2007-06-01) Ooka, Tadasuke; Vieira, Monica A. M. [UNIFESP]; Ogura, Yoshitoshi; Beutin, Lothar; La Ragione, Roberto; van Diemen, Pauline M.; Stevens, Mark P.; Aktan, Ilknur; Cawthraw, Shaun; Best, Angus; Hernandes, Rodrigo T. [UNIFESP]; Krause, Gladys; Gomes, Tania A. T. [UNIFESP]; Hayashi, Tetsuya; Frankel, Gad; Univ London Imperial Coll Sci Technol & Med; Miyazaki Univ; Universidade Federal de São Paulo (UNIFESP); Bundesinst Risikobewertung; Vet Labs Agcy
    Atypical enteropathogenic Escherichia coli (EPEC) comprise an important group of paediatric pathogens. Atypical EPEC have reservoirs in farm and domestic animals where they can be either commensal or pathogenic; serogroup O26 is dominant in humans and animals. Central to intestinal colonization by EPEC is the translocation of the type III secretion system effector Tir into enterocytes, which following phosphorylation (Tir-Yp) recruits Nck to activate the N-WASP actin signalling cascade. the authors have recently shown that typical EPEC strains, belonging to the EPEC-2 lineage, carry a tir gene encoding Tir-Yp and can also use the alternative TccP2 actin-signalling cascade. the aim of this study was to determine if tccP2 is found in atypical EPEC isolated from human and farm animals. tccP2 was found at a frequency of 41% in non-O26 EPEC isolates and in 82.3% of the O26 strains. TccP2 of human and animal strains show high level of sequence identity. It is shown that most strains carry a tir gene encoding Tir-Yp. in addition the authors identified two new variants of tir genes in EPEC O104:H12 and NT:H19 strains.
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    PLASMID CODING for DRUG-RESISTANCE and INVASION of EPITHELIAL-CELLS in ENTEROPATHOGENIC ESCHERICHIA-COLI-0111-H-
    (Academic Press (london) Ltd, 1995-06-01) Scaletsky, ICA; Gatti, MSV; Dasilveira, J. F.; Deluca, IMS; Freymuller, E.; Travassos, L. R.; Universidade Federal de São Paulo (UNIFESP); Universidade Estadual de Campinas (UNICAMP)
    Enteropathogenic Escherichia coli (EPEC) can adhere to, invade and multiply in human epithelial cells. To define the elements required for bacterial invasion, we isolated from an 0111:H- EPEC a 6.6 kb plasmid that is capable of conferring to an avirulent, non-adherent E. coli K12 strain (DK1) the capacity to invade epithelial cells. With this system a dissociation was possible between bacterial invasion and adherence to epithelial cells. Bacteria containing this plasmid synthesise a protein of 32 kDa (pi 4.93) which seemed to be required for cell invasion. the results provide a new basis for strategies to prevent EPEC infections.