Navegando por Palavras-chave "Virulence markers"

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    Ice as a vehicle for diarrheagenic Escherichia coli
    (Elsevier B.V., 2004-02-15) Falcao, Juliana Pfrimer; Falcao, Deise Pasetto; Gomes, Tania Aparecida Tardelli [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Univ Estadual Paulista
    In a recent study of the microbiological quality of commercial ice, 50 Escherichia coli isolates belonging to different serotypes were found. the potential hazard from these isolates was examined by testing their adherence patterns ill HeLa cells and searching for the presence of DNA sequences related to E. coli virulence properties. Twelve potentially diarrheagenic isolates were found and classified as enteroaggregative E. coli (EAEC) based oil their ability to produce aggregative adherence to HeLa cells. the remaining isolates were devoid of the virulence properties searched for. the EAEC isolates belonged to 10 different serotypes, among which O128ab:H35 is often found in diarrheic feces. None of these isolates reacted with a specific EAEC DNA probe or carried any of the known EAEC virulence genes. These data indicate that ice may be all important vehicle for transmission of enteropathogens, especially of the EAEC group. (C) 2003 Elsevier B.V. All rights reserved.
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    Serotypes, virulence markers and cell invasion ability of Shiga toxin-producing Escherichia coli strains isolated from healthy dairy cattle
    (Wiley-Blackwell, 2016) Gonzalez, Alice Gonçalves Martins; Cerqueira, Aloysio de Mello Figueiredo; Guth, Beatriz Ernestina Cabilio [UNIFESP]; Coutinho, Cesar Augusto de Souza; Liberal, Maira Halfen Teixeira; Souza, Rossiane de Moura; Andrade, João Ramos da Costa; Universidade Federal de São Paulo (UNIFESP)
    AimThe occurrence of virulence markers, serotypes and invasive ability were investigated in Shiga toxin-producing Escherichia coli (STEC) isolated from faecal samples of healthy dairy cattle at Rio de Janeiro State, Brazil. Methods and ResultsFrom 1562 stx-positive faecal samples, 105 STEC strains were isolated by immuno-magnetic separation (IMS) or plating onto MacConkey agar (MC) followed by colony hybridisation. Fifty (476%) strains belonged to nine serotypes (O8:H19, O22:H8, O22:H16, O74:H42, O113:H21, O141:H21, O157:H7, O171:H2 and ONT:H21). The prevalent serotypes were O157:H7 (124%), O113:H21 (67%) and O8:H19 (57%). Virulence genes were identified by polymerase chain reaction (PCR). E-hlyA (771%) was the more prevalent virulence marker, followed by espP (648%), saa (39%), eae (248%) and astA (219%). All O157:H7 strains carried the (gamma) variant of the locus of enterocyte effacement (LEE) genes and the stx2c gene, while the stx1/stx2 genotype prevailed among the eae-negative strains. None of the eae-positive STEC produced the localized adherence (LA) phenotype in HEp-2 or Caco-2 cells. However, intimate attachment (judged by the fluorescent actin staining test) was detected in some eae-positive strains, both in HEp-2 (231%) and in Caco-2 cells (115%). Most strains (875%) showed peripheral association' (PA) adherence phenotype to undifferentiated Caco-2 cells. Twenty-five (926%) of 27 strains invaded Caco-2 cells. The highest average value of invasion (96%) was observed among the eae-negative bovine strains from serotypes described in human disease. ConclusionHealthy dairy cattle is a reservoir of STEC carrying virulence genes and properties associated with human disease. Significance and Impact of the StudyAlthough reports of human disease associated with STEC are scarce in Brazil, the colonization of the animal reservoir by potentially pathogenic strains offers a significant risk to our population.