Serotypes and virulence markers of Shiga toxin-producing Escherichia coli (STEC) isolated from dairy cattle in São Paulo State, Brazil

Serotypes and virulence markers of Shiga toxin-producing Escherichia coli (STEC) isolated from dairy cattle in São Paulo State, Brazil

Author Irino, K. Google Scholar
Kato, MAMF Google Scholar
Vaz, TMI Google Scholar
Ramos, II Google Scholar
Souza, MAC Google Scholar
Cruz, A. S. Google Scholar
Gomes, TAT Google Scholar
Vieira, MAM Google Scholar
Guth, BEC Google Scholar
Institution Inst Adolfo Lutz Registro
Universidade de São Paulo (USP)
Universidade Federal de São Paulo (UNIFESP)
Abstract In order to determine the occurrence, serotypes and virulence markers of Shiga toxin-producing Escherichia coli (STEC) strains, 153 fecal samples of cattle randomly selected from six dairy farms in São Paulo State. Brazil. were examined for Shiga toxin (Stx) production by the Vero cell assay. Feces were directly streaked onto MacConkey Sorbitol Agar and incubated at 37degreesC overnight. Sorbitol-negative colonies (maximum 20) and up to 10 sorbitol-positive colonies from each plate were subcultured onto presumptive diagnostic medium IAL. Sorbitol-negative isolates were screened with O157 antiserum for identification of O157:H7 E. coli. Isolates presenting cytotoxic activity were submitted to colony hybridization assays with specific DNA probes for stx1, stx2, eae, Ehly and astA genes. the isolation rate of STEC ranged from 3.8 to 84.6% depending on the farm analysed. STEC was identified in 25.5% of the animals, and most of them (64.1%) carried a single STEC serotype. A total of 202 STEC isolates were recovered from the animals. and except for the 2 O157:H7 isolates all the others expressed cytotoxic activity. the great majority of the STEC isolates carried both stx1 and stx2 genes (114/202, 56-4%) or stx2 (82/202, 40.6%); and whereas the Ehly sequence occurred in most of them (88%) eae was only observed in O151:H7 and O111:HNM isolates. Serotypes O113:H21, O178:H19 and O79:H14 were the most frequent STEC serotypes identified and widely distributed among animals from different farms, while others such as O77:H18. O88:H25 and O98:H17 occurred only in particular farms. This is the first report on the occurrence of STEC in dairy cattle in São Paulo State. and the results point to substantial differences in rate of isolation. serotypes and genetic profile of STEC that has been previously described among beef cattle in our community. Moreover, to our knowledge O79:H14 and O98:H17 represent new STEC serotypes, while O178:H19 has only been recently reported in Spain. (C) 2004 Elsevier B.V. All rights reserved.
Keywords Escherichia coli O157
Shiga toxin-producing E. coli
dairy cattle
Language English
Date 2005-01-05
Published in Veterinary Microbiology. Amsterdam: Elsevier B.V., v. 105, n. 1, p. 29-36, 2005.
ISSN 0378-1135 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 29-36
Origin http://dx.doi.org/10.1016/j.vetmic.2004.08.007
Access rights Closed access
Type Article
Web of Science ID WOS:000226269200004
URI http://repositorio.unifesp.br/handle/11600/28110

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