Escherichia coli O157 in ground beef from local retail markets in Pachuca, Mexico

Abstract

Apoptotic activity of the alkaloid-enriched preparation (BSRT) obtained from the bark of the Amazonian woody vine Uncaria tomentosa was examined in vitro. We showed that promyelocytic leukemia HL-60 cells pretreated with BSRT (IC50 = 60 ?g/mL) enhance their response on proapoptotic TNF-? signals and this effect was two times higher in comparison to the control. This observation helps to demonstrate the hypothesis formulated on the basis of literature data that U. tomentosa inhibits NF-?B, and that cells unable to activate NF-?B are more sensitive to the proapoptotic stimuli. Qualitative and quantitative high pressure liquid chromatography analyses of BSRT suggest the pentacyclic oxindole alkaloids (POA) as main active compounds responsible for this effect, however, other phytochemicals should be also taken into consideration. " 2013 Elsevier GmbH. All rights reserved.",,,,,,"10.1016/j.hermed.2013.04.002",,,"http://hdl.handle.net/20.500.12104/41233","http://www.scopus.com/inward/record.url?eid=2-s2.0-84888639558&partnerID=40&md5=43b309578ddffb90b015dcb14e62e33b

http://ovidsp.ovid.com/ovidweb.cgi?T=JS&CSC=Y&NEWS=N&PAGE=fulltext&D=med3&AN=7704625",,,,,,"4",,"Journal of Herbal Medicine",,"149

156",,"3",,"Scopus

WOS

MEDLINE",,,,,,"Apoptosis; Cat's claw; Cytotoxicity; NF-?B; Pentacyclic oxindole alkaloids; TNF-?; Uncaria tomentosa",,,,,,"Enhanced proapoptotic response of the promyelocytic leukemia HL-60 cells treated with an Uncaria tomentosa alkaloid preparation",,"Article" "43013","123456789/35008","Beas-Zárate, C., Laboratorio de Neuroquímica, Facultad de Ciencias Biológicas, Universidad de Guadalajara, Guadalajara, Jalisco, Mexico; Morales-Villagran, A., Laboratorio de Neuroquímica, Facultad de Ciencias Biológicas, Universidad de Guadalajara, Guadalajara, Jalisco, Mexico; Ortuño, S.D., Laboratorio de Neuroquímica, Facultad de Ciencias Biológicas, Universidad de Guadalajara, Guadalajara, Jalisco, Mexico; Feria-Velasco, A., Universidad de Investigación Médica en Patología Experimental, Hospital de Oncología, Centro Médico Nacional, Siglo XXI, I.M.S.S., México, D.F., Mexico",,"Beas-Zárate, Carlos

Morales-Villagran, A.

Ortuno, S.D.

Feria-Velasco, A.",,"1995",,"l-Glutamate has an excitatory and cytotoxic effect on the central nervous system. It was shown previously that norepinephrine and dopamine uptake and release were affected by in vivo administration of glutamate to adult rats. The kinetic parameters, Km and Vmax of [14C]DA uptake and release were measured on synaptosomal and slices from caudate nucleus under in vitro conditions at different glutamate concentrations. Results showed an important increase in [14C]DA uptake on synaptosomal (> 100%) and slices by lower glutamate concentrations, the affinity for transport system was increased (100%) and its release of high potassium evoked was also increased at 0.5 ?M of glutamate. The results suggest the possibility that glutamate may modify DA uptake and release interacting with the DA transporter complex at the synaptic level. © 1995.",,,,,,"10.1016/0300-9629(94)00141-F",,,,"http://www.scopus.com/inward/record.url?eid=2-s2.0-0028815810&partnerID=40&md5=ee18a6b999742b56485e6ea36d66e3d5

http://hdl.handle.net/20.500.12104/41234",,,,,,"2",,"Comparative Biochemistry and Physiology -- Part A: Physiology",,"151

157",,"110",,"Scopus",,,,"Index Medicus;Animals;Caudate Nucleus/de [Drug Effects];Caudate Nucleus/me [Metabolism];Dopamine/me [Metabolism];In Vitro Techniques;Kinetics;Male;Rats;Rats, Wistar;Sodium Glutamate/pd [Pharmacology];Synaptosomes/de [Drug Effects];Synaptosomes/me [Metabolism]",,"Caudate; Dopamine; Glutamate; Monosodium glutamate; Nucleus; Release; Uptake",,,,"Enhancement in dopamine uptake and release induced by monosodium l-glutamate from caudate nucleus under in vitro conditions",,,,"Article", "43036","123456789/35008",,"Torres-Mancera, M.T., Department of Biotechnology, Metropolitan Autonomous University (UAM-I), Av. San Rafael Atlixco 186, Vicentina 09340, D.F. Mexico, Mexico; Cordova-López, J., University of Guadalajara (CUCEI), Blvd. Marcelino García Barragán 1421, Olímpica-44430 Guadalajara, Jalisco State, Mexico; Rodríguez-Serrano, G., Department of Biotechnology, Metropolitan Autonomous University (UAM-I), Av. San Rafael Atlixco 186, Vicentina 09340, D.F. Mexico, Mexico; Roussos, S., Department of Microbial Ecology and Biotechnology, Paul Cezanne University, FST Avenue Escadrille Normandie Niemen, FR-13397 Marseille Cedex 20, France; Ramírez-Coronel, M.A., Department of Biotechnology, Metropolitan Autonomous University (UAM-I), Av. San Rafael Atlixco 186, Vicentina 09340, D.F. Mexico, Mexico; Favela-Torres, E., Department of Biotechnology, Metropolitan Autonomous University (UAM-I), Av. San Rafael Atlixco 186, Vicentina 09340, D.F. Mexico, Mexico; Saucedo-Castañeda, G., Department of Biotechnology, Metropolitan Autonomous University (UAM-I), Av. San Rafael Atlixco 186, Vicentina 09340, D.F. Mexico, Mexico",,"Torres-Mancera, M.T.

Cordova-Lopez, J.

Rodriguez-Serrano, G.

Roussos, S.

Ramirez-Coronel, M.A.

Favela-Torres, E.

Saucedo-Castaneda, G.",,"2011",,"Ferulic, caffeic, p-coumaric and chlorogenic acids are classified as hydroxycinnamic acids, presenting anticarcinogenic, anti-inflammatory and antioxidant properties. In this work, enzymatic extraction has been studied in order to extract high value-added products like hydroxycinnamic acids from coffee pulp. A commercial pectinase and enzyme extract produced by Rhizomucor pusillus strain 23aIV in solid-state fermentation using olive oil or coffee pulp (CP) as an inducer of the feruloyl esterase activity were evaluated separately and mixed. The total content (covalently linked and free) of ferulic, caffeic, p-coumaric and chlorogenic acids was 5276 mg per kg of coffee pulp. Distribution was as follows (in %): chlorogenic acid 58.7, caffeic acid 37.6, ferulic acid 2.1 and p-coumaric acid 1.5. Most of the hydroxycinnamic acids were covalently bound to the cell wall (in %): p-coumaric acid 97.2, caffeic acid 94.4, chlorogenic acid 76.9 and ferulic acid 73.4. The content of covalently linked hydroxycinnamic acid was used to calculate the enzyme extraction yield. The maximum carbon dioxide rate for the solid-state fermentation using olive oil as an inducer was higher and it was reached in a short cultivation time. Nevertheless, the feruloyl esterase (FAE) activity (units per mg of protein) obtained in the fermentation using CP as an inducer was 31.8 % higher in comparison with that obtained in the fermentation using olive oil as the inducer. To our knowledge, this is the first report indicating the composition of both esterified and free ferulic, caffeic, p-coumaric and chlorogenic acids in coffee pulp. The highest yield of extraction of hydroxycinnamic acids was obtained by mixing the produced enzyme extract using coffee pulp as an inducer and a commercial pectinase. Extraction yields were as follows (in %): chlorogenic acid 54.4, ferulic acid 19.8, p-coumaric acid 7.2 and caffeic acid 2.3. An important increase in the added value of coffee pulp was mainly due to the extraction of chlorogenic acid.",,,,,,,,,"http://hdl.handle.net/20.500.12104/41257","http://www.scopus.com/inward/record.url?eid=2-s2.0-80053320293&partnerID=40&md5=a5f4882dd4de9ef30dc982fbb13a87da",,,,,,"3",,"Food Technology and Biotechnology",,"369

373",,"49",,"Scopus

WOS",,,,,,"Antioxidants; Coffee pulp; Hydroxycinnamic acids; Olive oil; Solid-state fermentation",,,,,,"Enzymatic extraction of hydroxycinnamic acids from coffee pulp",,"Article" "43099","123456789/35008","González-Cuevas, J., Instituto de Biología Molecular en Medicina y Terapia Génica, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara, Jalisco 44340, Mexico; Navarro-Partida, J., Instituto de Biología Molecular en Medicina y Terapia Génica, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara, Jalisco 44340, Mexico; Marquez-Aguirre, A.L., Centro de Investigación y Asistencia en Tecnología, Diseño del Estado de Jalisco, CIATEJ, Guadalajara, Jalisco, Mexico; Bueno-Topete, M.R., Instituto de Biología Molecular en Medicina y Terapia Génica, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara, Jalisco 44340, Mexico; Beas-Zarate, C., Departamento de Biologia Celular y Molecular, CUCBA, Universidad de Guadalajara, Mexico; Armendáriz-Borunda, J., Instituto de Biología Molecular en Medicina y Terapia Génica, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara, Jalisco 44340, Mexico, O.P.D. Hospital Civil de Guadalajara, Guadalajara, Jalisco, Mexico

Beas-Zárate, Carlos., Universidad de Guadalajara. Centro Universitario de Ciencias Biológicas y Agropecuarias",,"Gonzalez-Cuevas, J.

Navarro-Partida, J.

Marquez-Aguirre, A.L.

Bueno-Topete, M.R.

Beas-Zárate, Carlos

Armendariz-Borunda, J.",,"2011",,"Background: Experimental liver fibrosis induced by carbon tetrachloride (CCl4) is associated with oxidative stress, lipid peroxidation, and inflammation. This work was focused on elucidating the anti-inflammatory and antioxidant effects of ethylenediaminetetraacetic acid (EDTA) in this model of hepatotoxicity Methods: Wistar male rats were treated with CCl4 and EDTA (60, 120, or 240 mg/kg). Morphometric analyses were carried out in Masson's stained liver sections to determine fibrosis index. Coagulation tests prothrombin time (PT) and partial thromboplastin time (PTT) were also determined. Gene expression for transforming growth factor beta (TGF-beta1), alpha1(I) procollagen gene (alpha1 Col I), tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), and superoxide dismutase (SOD) was monitored by real-time PCR. Antioxidant effect of EDTA was measured by its effects on lipid peroxidation; biological activity of ceruloplasmin (Cp), SOD, and catalase (Cat) were analyzed by zymography assays. Results: Animals with CCl4-hepatic injury that received EDTA showed a decrement in fibrosis (20%) and lipid peroxidation (22%). The mRNA expression for TNF-alpha (55%), TGF-beta1 (50%), IL-6 (52%), and alpha1 Col I (60%) was also decreased. This group of animals showed increased Cp (62%) and SOD (25%) biological activities. Coagulation blood tests, Cat activity, and gene expression for SOD were not modifiedby EDTA treatment. Conclusion: This study demonstrates that EDTA treatment induces the activity of antioxidant enzymes, decreases lipid peroxidation, hepatic inflammation, and fibrosis in experimental liver fibrosis induced by CCl4. © W.S. Maney & Son Ltd.",,,,,,"10.1179/174329211X13002357050851",,,,"http://www.scopus.com/inward/record.url?eid=2-s2.0-79959830695&partnerID=40&md5=709b9165540c503dc544d4d6e82717a7

http://ovidsp.ovid.com/ovidweb.cgi?T=JS&CSC=Y&NEWS=N&PAGE=fulltext&D=medl&AN=21722414

http://hdl.handle.net/20.500.12104/41320",,,,,,"2",,"Redox Report",,"62

70",,"16",,"Scopus

MEDLINE

WOS",,,,"Index Medicus;Animals;Anti-Inflammatory Agents/tu [Therapeutic Use];Anticoagulants/tu [Therapeutic Use];Antioxidants/tu [Therapeutic Use];Blotting, Western;Carbon Tetrachloride Poisoning;Catalase/ge [Genetics];Catalase/me [Metabolism];Edetic Acid/tu [Therapeutic Use];Immunoenzyme Techniques;Inflammation/ci [Chemically Induced];Inflammation/dt [Drug Therapy];Inflammation/me [Metabolism];Interleukin-6/ge [Genetics];Interleukin-6/me [Metabolism];Lipid Peroxidation;Liver/de [Drug Effects];Liver/me [Metabolism];Liver Cirrhosis/ci [Chemically Induced];Liver Cirrhosis/dt [Drug Therapy];Liver Cirrhosis/me [Metabolism];Male;Oxidative Stress/de [Drug Effects];RNA, Messenger/ge [Genetics];Rats;Rats, Wistar;Reverse Transcriptase Polymerase Chain Reaction;Superoxide Dismutase/ge [Genetics];Superoxide Dismutase/me [Metabolism];Transforming Growth Factor beta/ge [Genetics];Transforming Growth Factor beta/me [Metabolism];Tumor Necrosis Factor-alpha/ge [Genetics];Tumor Necrosis Factor-alpha/me [Metabolism]",,,,,,"Ethylenediaminetetraacetic acid induces antioxidant and anti-inflammatory activities in experimental liver fibrosis",,,,"Article", "43052","123456789/35008","Vallés, E., Planta Piloto en Ingeniería Química, Bahía Blanca 8000, Argentina; Durando, D., Planta Piloto en Ingeniería Química, Bahía Blanca 8000, Argentina; Katime, I., Grupo de Nuevos Materiales, Departamento de Química Física, Universidad del País Vasco - Campus Leioa, 48080 Bilbao, Spain; Mendizábal, E., Departamentos de Química y de Ingeniería Química, Universidad de Guadalajara, Boul. M. García Barragan # 1455, Guadalajara, Jal. 44430, Mexico; Puig, J.E., Departamentos de Química y de Ingeniería Química, Universidad de Guadalajara, Boul. M. García Barragan # 1455, Guadalajara, Jal. 44430, Mexico

Mendizábal, E. M., Universidad de Guadalajara. Centro Universitario de Ciencias Exactas e Ingenierías",,"Valles, E.

Durando, D.

Katime, I.

Mendizábal, E. M.

Puig, J.E.",,"2000",,"The equilibrium swelling and the plateau elastic modulus of a family of hydrogels made by the polymerization of acrylamide with itaconic acid or some of its esters were investigated as a function of composition and crosslinking degree to find materials with satisfactory swelling and elastic properties. We show that an appropriate selection of the comonomers and the concentration of the crosslinking agent is very important to produce hydrogels with large swelling capacity and good mechanical attributes. Tailoring of mechanical properties and swelling can also be achieved by this method.",,,,,,,,,,"http://www.scopus.com/inward/record.url?eid=2-s2.0-0033652448&partnerID=40&md5=1e23868b097aae76ba067f9bb8e71c1a

http://hdl.handle.net/20.500.12104/41273",,,,,,"1",,"Polymer Bulletin",,"109

114",,"44",,"Scopus

WOS",,,,,,,,,,"Equilibrium swelling and mechanical properties of hydrogels of acrylamide and itaconic acid or its esters",,,,"Article", "43029","123456789/35008",,"Macías Macías, A., Universidad de Guadalajara, Mexico, Centro de Investigaciones Y Estudios Superiores en Antropología Social-CIESAS, Mexico, Centro Universitario del Sur, Universidad de Guadalajara, Mexico, Sociedad de Geografía Y Estadística de México, Mexico, Prol. Colon, S/N, Km. 1, carretera Cd. Guzman, Guadalajara, C. P. 49000, Cd. Guzmán. Jalisco, Mexico",,"Macias Macias, A.",,"2008",,"For about twenty years in Sayula, the agro-industrial production of vegetables was carried out by companies from other regions of the country, which valued the territory like agricultural juncture zones as they had done in other parts of Mexico. This productive model, where practices like intensive agriculture and monocultures predominate, has generated a diversity of environmental effects, whose monetary quantification becomes important to take corrective measures. In this article, the author applied a survey to a sample of Sayula population (México), in order to inquiry about its perception of consequences of such production, as well as to estimate their economic cost, by using the contingent valuation method.",,,,,,,,,"http://hdl.handle.net/20.500.12104/41250","http://www.scopus.com/inward/record.url?eid=2-s2.0-59349115992&partnerID=40&md5=24524c0efe3419ae06746c0555475f0e",,,,,,"26",,"Agroalimentaria",,"103

118",,"13",,"Scopus",,,,,,"Agricultural conjuncture zones; Contingent valuation; Environmental costs; Mexico; Sayula; Vegetables",,,,,,"Environmental costs in agricultural conjuncture zones. Vegetable cultivation in Sayula (Mexico) [Costos ambientales en zonas de coyuntura agrícola. La horticultura en sayula (México)]",,"Review" "43049","123456789/35008",,"Bernal-Orozco, M.F., Departamento de Clínicas de la Reproducción Humana, Centro Universitario de Ciencias de la Salud, UDG-CA-454, Guadalajara, Mexico, Doctorado en Ciencias de la Salud Pública, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara, Mexico; Vizmanos, B., Departamento de Clínicas de la Reproducción Humana, Centro Universitario de Ciencias de la Salud, UDG-CA-454, Guadalajara, Mexico, Doctorado en Ciencias de la Salud Pública, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara, Mexico; Hunot, C., Departamento de Clínicas de la Reproducción Humana, Centro Universitario de Ciencias de la Salud, UDG-CA-454, Guadalajara, Mexico; Flores-Castro, M., Servicio de Geriatría, OPD Antiguo Hospital Civil de Guadalajara Fray Antonio Alcalde, Guadalajara, Mexico, Departamento de Clínicas Médicas, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara, Mexico; Leal-Mora, D., Servicio de Geriatría, OPD Antiguo Hospital Civil de Guadalajara Fray Antonio Alcalde, Guadalajara, Mexico, Departamento de Clínicas Médicas, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara, Mexico; Cells, A., Doctorado en Ciencias de la Salud Pública, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara, Mexico; Fernández-Ballart, J.D., Unidad de Medicina Preventiva y Salud Pública, Universitat Rovira i Virgili, Reus, Spain",,"Bernal-Orozco, M.F.

Vizmanos, B.

Hunot, C.

Flores-Castro, M.

Leal-Mora, D.

Cells, A.

Fernandez-Ballart, J.D.",,"2010",,"Introduction: Body weight is useful for many medical and nutritional procedures. When it is difficult or impossible to measure body weight in hospitalized/institutionalized elderly, it can be estimated through equations based on anthropometry generated in other countries, although their validity in other contexts has been poorly studied. Objectives: To create and validate an equation for estimating body weight for both, hospitalized and nursing home residents Mexican elderly women (institutionalized) using anthropometric measurements. Methods: A validation study was carried out in elderly women (? 60 years old), admitted to the Geriatrics Service of the Hospital Civil de Guadalajara "Fray Antonio Alcalde" during February-April 19th (n = 43) and April 20th-June 2005 (n = 29), and elderly women residing in three nursing homes in the Metropolitan Area of Guadalajara evaluated during June 2003-June 2004 (n = 23). Subjects were weighed using a scale which was adapted to their clinical situation and were anthropometrically assessed. In the first sample, we generated a new equation using multiple regression analyses. Then, the equation was validated in the other two samples. We also estimated weight using Chumlea's equations: in all samples, estimated and actual weights were compared between each other through a paired t-test. A p < 0.05 was considered as significant. Results: Mean ages in each sample were: 84.3 7.3, 84.4 9.1, and 84.2 8.5 years, respectively. Mean actual weights were: 48.2 13.5, 48.1 10.1, and 55.0 12.3 kg, respectively. The resulting equation was: estimated weight = (1.599* knee height) +(1.135* mid arm circumference) + (0.735*calf circumference) + (0.621* tricipital skinfold thickness)-83.123 (R2 = 0.896, p < 0.001). In hospitalized women, there were no significant differences between estimated and actual weight (sample 1:D-0.02 4.3kg, p = 0.976; sample 2: D-0.7 4.2 kg, p = 0.352). In female nursing homes residents (institutionalized women) weight was significantly overestimated (1.9 3.2 kg p < 0.01), but the mean difference was smaller than the ones found using Chumlea's equations. Conclusions: The developed equation predicted accurately hospitalized elderly women's body weight in our context. In institutionalized elderly women, weight was significantly overestimated. It would be useful to derive equations for different settings.uals who present normal body weight.",,,,,,"10.3305/nh.2010.25.4.4508",,,"http://hdl.handle.net/20.500.12104/41270","http://www.scopus.com/inward/record.url?eid=2-s2.0-77954780881&partnerID=40&md5=379bdb85d5a4615aa6f3eb3851bd0719

MEDLINE",,,,,,"4",,"Nutricion Hospitalaria",,"648

655",,"25",,"Scopus

WOS

http://ovidsp.ovid.com/ovidweb.cgi?T=JS&CSC=Y&NEWS=N&PAGE=fulltext&D=med5&AN=20694303",,,,"Index Medicus;Aged;Anthropometry;Body Weight;Female;Humans;Mathematics;Mexico",,"Anthropometry; Body weight and measures; Elderly / Political Science; Sociology",,,,,,"Equation to estimate body weight in elderly Mexican women using anthropometric measurements",,"Article" "43069","123456789/35008",,"Gómez-Aldapa, C.A., Instituto de Ciencias Básicas e Ingeniería, Universidad Autónoma del Estado de Hidalgo, Centro Universitario, Carretera Pachuca-Tulancingo Km. 4.5, 42183 Mineral de la Reforma, Hidalgo, Mexico; Díaz-Cruz, C.A., Instituto de Ciencias Básicas e Ingeniería, Universidad Autónoma del Estado de Hidalgo, Centro Universitario, Carretera Pachuca-Tulancingo Km. 4.5, 42183 Mineral de la Reforma, Hidalgo, Mexico; Cerna-Cortes, J.F., Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas-IPN, Prolongación Carpio y Plan de Ayala s/n, Col. Casco de Santo Tomas, 11340 Mexico, Mexico; Torres-Vitela, M.D.R., Laboratorio de Microbiología Sanitaria, Centro Universitario de Ciencias Exactas e Ingeniería, Universidad de Guadalajara, Marcelino García Barragán 1451, 44430 Guadalajara, Jalisco, Mexico; Villarruel-López, A., Laboratorio de Microbiología Sanitaria, Centro Universitario de Ciencias Exactas e Ingeniería, Universidad de Guadalajara, Marcelino García Barragán 1451, 44430 Guadalajara, Jalisco, Mexico; Rangel-Vargas, E., Instituto de Ciencias Básicas e Ingeniería, Universidad Autónoma del Estado de Hidalgo, Centro Universitario, Carretera Pachuca-Tulancingo Km. 4.5, 42183 Mineral de la Reforma, Hidalgo, Mexico; Castro-Rosas, J., Instituto de Ciencias Básicas e Ingeniería, Universidad Autónoma del Estado de Hidalgo, Centro Universitario, Carretera Pachuca-Tulancingo Km. 4.5, 42183 Mineral de la Reforma, Hidalgo, Mexico",,"Gomez-Aldapa, C.A.

Diaz-Cruz, C.A.

Cerna-Cortes, J.F.

Torres-Vitela, M.D.R.

Villarruel-Lopez, A.

Rangel-Vargas, E.

Castro-Rosas, J.",,"2013",,"Escherichia coli O157 strains have been recognized as pathogenic bacteria, of which raw beef is a known vehicle. An evaluation was done of the presence of E. coli O157 in ground beef from local retail markets in Pachuca, Hidalgo State, Mexico. A total of 120 ground beef samples (500 g) were tested for E. coli O157 by simultaneous application of the U.S. Department of Agriculture, Food Safety and Inspection Service (FSIS)'s Microbiology Laboratory Guidebook culture procedure 5.05, and two commercial kits, Reveal for E. coli O157:H7 and Visual Immunoprecipitate Assay (VIP) Gold for enterohemorrhagic E. coli. Two incubation times (8 and 20 h) were used with the commercial kits. Presence of stx 1, stx2, and eaeA loci was determined by multiplex PCR. Of 360 subsamples (120 per procedure), 12 samples were found to be E. coli O157 positive by the FSIS culture method. With VIP, 73 subsamples were presumptive positive after 8 h of enrichment, and 60 were presumptive positive after 20 h of enrichment. Of these, only 6 (8 h) and 8 (20 h) subsamples were confirmed true positives with the FSIS method. With Reveal, 60 subsamples were presumptive positive after 8 h of enrichment and 50 were presumptive positive after 20 h of enrichment. Of these, only 6 (8 h) and 8 (20 h) subsamples were confirmed as true positives with the FSIS method. A total of 57 E. coli O157:H7 and 21 E. coli O157 strains were isolated. None of the O157 or O157:H7 strains had stx1 or stx2 loci, and only one had the eaeA locus. To our knowledge, this is the first report of the presence of E. coli O157 in commercial ground beef from Mexico, and the first report of isolation of a large number of stx-negative E. coli O157 and E. coli O157:H7 strains in Mexico. " International Association for Food Protection.