Please use this identifier to cite or link to this item: https://hdl.handle.net/20.500.12104/42407
Title: Isolation and characterization of Shiga toxin-producing Escherichia coli O157:H7 and non-O157 from beef carcasses at a slaughter plant in Mexico
Author: Olvera-Vargas, M.
Figueroa-Rangel, B.L.
Vazquez-Lopez, J.M.
Issue Date: 2010
Abstract: Detailed information on 38 species and 26 environmental variables was recorded from a network of 86 permanent plots across a geographical range of 10 km, in order to determine the patterns of floristic composition in Quercus-dominated forests; to elucidate environmental differentiation in such forests; and to determine whether species are partitioning their environment. To examine likely patterns of floristic composition, a data matrix expressed as relative volume + relative density was used to run non-metric multidimensional scaling. Canonical correspondence analysis extracted the environmental variation that best correlates with the observed patterns of floristic composition. Our results indicate that congeneric Quercus individuals represent the largest proportion of the species pool in the study plots. They coexist with other species having similar ecological requirements in at least three distinct floristic groups. Examination of the two largest groups and their species compositions reveals that one floristic gradient runs across the most xeric zone of the study area, and the second major floristic gradient runs across a mesic zone. The most important environmental variable explaining the observed patterns of floristic composition is altitude, although partial canonical correspondence analysis suggests that micro-habitat heterogeneity (catena position and canopy maturity) was most significant. " Springer Science+Business Media B.V. 2010.",,,,,,"10.1007/s11258-010-9792-z",,,"http://hdl.handle.net/20.500.12104/42407","http://www.scopus.com/inward/record.url?eid=2-s2.0-78650715324&partnerID=40&md5=0e752bd8e4a8a8bc98da5ace20635f21",,,,,,"2",,"Plant Ecology",,"321
335",,"211",,"Scopus
WOS",,,,,,"Coexistence; Congeneric species; Environmental heterogeneity; Floristic composition; Quercus",,,,,,"Is there environmental differentiation in the Quercusdominated forests of west-central Mexico?",,"Article" "44191","123456789/35008",,"Varela-Hernández, J.J., Departamento de Ciencias Básicas, Centro Universitario de la Ciénega, Universidad de Guadalajara, Av. Universidad 1115, Ocotlán, Jalisco, C. P. 47840, Mexico; Cabrera-Diaz, E., Departamento de Salud Pública, Centro Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, Zapopan, Jalisco, Mexico; Cardona-López, M.A., Departamento de Ciencias Básicas, Centro Universitario de la Ciénega, Universidad de Guadalajara, Av. Universidad 1115, Ocotlán, Jalisco, C. P. 47840, Mexico; Ibarra-Velázquez, L.M., Departamento de Ciencias Básicas, Centro Universitario de la Ciénega, Universidad de Guadalajara, Av. Universidad 1115, Ocotlán, Jalisco, C. P. 47840, Mexico; Rangel-Villalobos, H., Departamento de Ciencias Básicas, Centro Universitario de la Ciénega, Universidad de Guadalajara, Av. Universidad 1115, Ocotlán, Jalisco, C. P. 47840, Mexico; Castillo, A., Department of Animal Science, Texas A and M University, College Station, TX, United States; Torres-Vitela, M.R., Departamento de Farmacobiología, Centro Universitario de Ciencias Exactas e Ingenierías, Universidad de Guadalajara, Guadalajara, Jalisco, Mexico; Ramírez-Álvarez, A., Departamento de Salud Pública, Centro Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, Zapopan, Jalisco, Mexico",,"Varela-Hernandez, J.J.
Cabrera-Diaz, E.
Cardona-Lopez, M.A.
Ibarra-Velazquez, L.M.
Rangel-Villalobos, H.
Castillo, A.
Torres-Vitela, M.R.
Ramirez-Alvarez, A.",,"2007",,"The contamination of beef carcasses with Shiga toxin-producing O157:H7 and non-O157 Escherichia coli (STEC) obtained from a slaughter plant in Guadalajara, Mexico was investigated. A total of 258 beef carcasses were sampled during a 12-month period. All samples were assayed for STEC by selective enrichment in modified tryptone soy broth supplemented with cefixime, cefsulodin and vancomycin, followed by plating on Sorbitol MacConkey Agar supplemented with cefixime and tellurite (CT-SMAC). Simultaneously, all samples were assayed by immunomagnetic separation (IMS) and plated on CT-SMAC and CHROMagar™. The presence of the stx1, stx2, eaeA and hly933 genes, recognized as major virulence factors of STEC, was tested for O157:H7 and non-O157 E. coli isolates by multiplex polymerase chain reaction (PCR). STEC was detected in two (0.8%) samples. One of these STEC isolates corresponded to the serotype O157:H7 showing stx2, eaeA and hyl933 genes. The other isolate corresponded to non-O157 STEC and only had the stx1 gene. Thirteen carcasses (5%) were positive for nonmotile E. coli O157 and 7 (2.7%) were positive for E. coli O157:H7. The presence of O157:H7 and non-O157 STEC on beef carcasses in this slaughter plant in Guadalajara, Mexico, emphasizes the importance of implementing the Hazard Analysis and Critical Control Point (HACCP) system, as well as the need for implementing, evaluating, and validating antimicrobial interventions to reduce the presence of potential pathogenic microorganisms. " 2006.
URI: http://hdl.handle.net/20.500.12104/42412
http://www.scopus.com/inward/record.url?eid=2-s2.0-33845992580&partnerID=40&md5=aaad1e9bb9340b8b3dbe8abbddcb4922
http://ovidsp.ovid.com/ovidweb.cgi?T=JS&CSC=Y&NEWS=N&PAGE=fulltext&D=med5&AN=17007951
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