Expression of EPL1 from Trichoderma atroviride in Arabidopsis Confers Resistance to Bacterial and Fungal Pathogens.

During plant interaction with beneficial microorganisms, fungi secrete a battery of elicitors that trigger plant defenses against pathogenic microorganisms. Among the elicitor molecules secreted by Trichoderma are cerato-platanin proteins, such as EPL1, from Trichoderma atroviride. In this study, Arabidopsis thaliana plants that express the TaEPL1 gene were challenged with phytopathogens to evaluate whether expression of EPL1 confers increased resistance to the bacterial pathogen Pseudomonas syringae and the necrotrophic fungus Botrytis cinerea. Infection assays showed that Arabidopsis EPL1-2, EPL1-3, EPL1-4 expressing lines were more resistant to both pathogens in comparison to WT plants. After Pseudomonas syringae infection, there were reduced disease symptoms (e.g., small chlorotic spots) and low bacterial titers in the three 35S::TaEPL1 expression lines. Similarly; 35S::TaEPL1 expression lines were more resistant to Botrytis cinerea infection, showing smaller lesion size in comparison to WT. Interestingly, an increase in ROS levels was detected in 35S::TaEPL1 expression lines when compared to WT. A higher expression of SA- and JA-response genes occurred in the 35S::TaEPL1 lines, which could explain the resistance of these EPL1 expression lines to both pathogens. We propose that EPL1 is an excellent elicitor, which can be used to generate crops with improved resistance to broad-spectrum diseases.

Mixed elicitation with salicylic acid and hydrogen peroxide modulates the phenolic and iridoid pathways in Castilleja tenuiflora plants.

MAIN CONCLUSION: SA and H2O2, in single and mixed elicitation stimulate specialized metabolism and activate oxidative stress in C. tenuiflora plants. Single elicitation with salicylic acid (SA at 75 µM) and, hydrogen peroxide (at 150 µM), and mixed elicitation (75 µM SA + 150 µM H2O2) were evaluated on specialized metabolism in Castilleja tenuiflora Benth. plants. Total phenolic content (TPC), phenylalanine ammonia-lyase (PAL) activity, antioxidant enzymes and specialized metabolite profiles, as well as the expression levels of eight genes involved in phenolic (Cte-TyrDC, Cte-GOT2, Cte-ADD, Cte-AO3, Cte-PAL1, Cte-CHS1) and terpene pathways (Cte-DXS1 and Cte-G10H) and their correlation with major metabolite (verbascoside and aucubin) concentrations were investigated. TPC content (three-fold) and PAL activity (11.5-fold) increased with mixed elicitation, as well as catalase and peroxidase activity (11.3-fold and 10.8-fold, respectively), compared to single elicitation. Phenylethanoid accumulation was greatest under mixed elicitation, followed by SA and H2O2. Lignan accumulation was differential, depending on the plant part and the elicitor. Flavonoids only appeared after mixed elicitation. The high concentration of verbascoside under mixed elicitation was related to a high gene expression. Single elicitation induced iridoid accumulation in specific parts (H2O2 in aerial parts and SA in roots), whereas under mixed elicitation, it accumulated in both parts. A high concentration of aucubin in the aerial part was related to a high expression level of genes of the terpene pathway Cte-DXS1 and Cte-G10H, and in the root with Cte-G10H, while Cte-DXS1 was downregulated in this tissue in all treatments. Mixed elicitation with SA and H2O2 represents an interesting tool to increase the production of specialized metabolites in plants.

Tumor Molecular Profiling in Hispanics: Moving Towards Precision Oncology and Health Equity.

BACKGROUND: Tumor molecular profiling techniques, such as next-generation sequencing (NGS) to identify somatic genetic alterations, allow physicians to have a better understanding of the affected carcinogenic pathways and guide targeted therapy. The objective of our study was to characterize common somatic alterations and carcinogenic pathways among Puerto Rican Hispanics with solid tumors. METHODS: We conducted a single-institution, retrospective study to characterize molecular tumor profiles using a 592-gene NGS platform. Actionable mutations with current or developing therapies targeting affected genes/pathways were highlighted. RESULTS: Tumors from 50 Hispanic patients were evaluated using CARIS Life Science© NGS testing. The median age of our study population was 55 (range 21-84); 54% (n = 27) were males. The primary tumor sites were colorectal (n = 24), gastric (n = 5), breast (n = 4), and lung (n = 3). The most common genetic mutations identified were in TP53 (44%), APC (38%), and KRAS (32%); followed by alterations in EGFR (4%), HER2 (6%), and homologous recombinant deficiency genes (BRCA2, 6%). Genetic alterations were found in multiple signaling pathways particularly in the cell cycle control pathway, MAPK and Wnt/ß-Catenin signaling pathways. Targetable biomarkers were identified in 27/50 (54.0%) of tumors. DISCUSSION: Molecular profiling techniques, such as next-generation sequencing, have substantially expanded access to alterations in the cancer genome. Our findings demonstrated important actionable mutations in most of the tumors evaluated and support the integration of somatic mutation profiling in the evaluation of Hispanic cancer patients with advanced cancer to help guide therapeutic options.

Efficacy of Bromhexine versus Standard of Care in Reducing Viral Load in Patients with Mild-to-Moderate COVID-19 Disease Attended in Primary Care: A Randomized Open-Label Trial.

A 28-day randomized open-label multicenter study was conducted to assess the efficacy of bromhexine plus standard of care (SOC) (n = 98) vs. SOC alone (n = 93) in 191 outpatients with mild-to-moderate COVID-19 in the primary health care setting. Bromhexine three daily doses of 10 mL (48 mg/day) were administered for seven days. The primary efficacy endpoint was the reduction of viral load estimated as the cycle thresholds (Ct) to detect ORF1ab, N Protein, and S Protein genes by RT-qPCR in saliva samples on day 4 as compared with baseline. Ct values of the three genes increased from baseline throughout days 4 to 14 (p < 0.001) but significant differences between the study groups were not found. Differences in the percentages of patients with low, medium, and high viral loads at 4, 7, and 14 days were not found either. In summary, treatment with bromhexine plus SCO was associated with a viral load reduction of ORF1ab, N Protein, and S Protein genes at day 4, which was not significantly different than similar viral load reductions observed with SOC alone. The present findings do not seem to favor the use of bromhexine as an antiviral in patients with COVID-19.

Intensidad del trabajo de conocimiento en la gestión de seguridad y salud en el trabajo / Intensity of the knowledge work in the occupational health and safety management activities

Introducción: La mejor gestión de seguridad y salud en el trabajo es la que practica la prevención; su eficacia se basa en conocimientos especializados para la evaluación de riesgos y la búsqueda de buenas soluciones. De ahí que el éxito dependa de la comprensión de la intensidad de conocimiento que requiere cada vez más esta tarea. Objetivo: Analizar la intensidad de trabajo de conocimiento que demanda la gestión de la seguridad y salud en el trabajo en una empresa. Métodos: El estudio se llevó a cabo en la Empresa Nacional de Análisis y Servicios Técnicos durante el periodo en que se realizó la investigación para la acreditación de su sistema de gestión de la seguridad y salud en el trabajo por la NC ISO 45001. Se evaluó la intensidad de trabajo de conocimiento a partir de la descomposición del trabajo en tareas, las que se evaluaron según las dimensiones de: calificación requerida, autonomía, innovación, intensidad de información, interdependencias y variabilidad de las situaciones. Se calculó la intensidad total, el aporte de cada tarea y de cada dimensión. Resultados: La dimensión más demandante fue la intensidad de información, tanto por lo referido a aspectos tecnológicos como a aspectos médicos y legales. Las tareas con más demanda de intensidad de conocimiento fueron la identificación de peligros y evaluación de riesgos, la capacitación de los trabajadores y la relacionada con la realización y análisis de chequeos médicos. Conclusiones: La efectividad de la gestión de la salud y seguridad en las empresas requiere de apoyos informáticos que respondan a sus necesidades e intercambios sistemáticos interdisciplinares entre ingenieros, psicólogos y médicos dedicados a la salud y seguridad ocupacional(AU)

Introduction: The best management of work safety and health is the practice of prevention; its efficiency is based in specialized knowledge for the assessment of risks and the search of good solutions. Therefore, the success depends on the comprehension of the knowledge intensity that this task requires. Objective: Analyze the intensity of the knowledge work that demands the management of safety and health in the functions of a company. Methods: The study was carried out in the National Company of Analysis and Technical Services during the period when it was performed the research for the accreditation of their Occupational health and safety management system by the NC ISO 45001. It was assessed the intensity of knowledge work from the division of the work in tasks, which were assessed according to the dimensions: required calification, autonomy, innovation, intensity of information, interdependencies and variability of the situations. It was calculated the overall intensity, the contribution of each task and of each dimension. Results: The most demanding dimension was the intensity of information, because of the technological aspects as well as due to the medical and legal aspects. The tasks with most demand of knowledge intensity were: the identification of dangers and assessment of risks, the training of workers, and the one related with the conduction and analysis of medical checkings. Conclusions: The effectiveness of health and safety's management in companies requires informatics supports that actually respond to their needs, and interdisciplinary systematic exchanges among engineers, psychologists and physicians devoted to occupational health and security(AU)

The Ustilago maydis null mutant strains of the RNA-binding protein UmRrm75 accumulate hydrogen peroxide and melanin.

Ustilago maydis is a dimorphic fungus that has emerged as a model organism for the study of fungal phytopathogenicity and RNA biology. In a previous study, we isolated the U. maydis UmRrm75 gene. The deletion of the UmRrm75 gene affected morphogenesis and pathogenicity. UmRrm75 gene encodes a protein containing three RNA recognition motifs. Here we determined that UmRrm75 has chaperone activity in Escherichia coli using the transcription anti-termination assay. Subsequently, we analyzed the growth of ΔUmRrm75 mutants at 15 °C and 37 °C, observing that mutant strains had reduced growth in comparison to parental strains. UmRrm75 gene expression was induced under these non-optimal temperatures. ΔUmRrm75 mutant colonies displayed a dark-brown color at 28 °C, which was confirmed to be melanin based on spectroscopic analysis and spectrometric data. Furthermore, ΔUmRrm75 mutant strains showed the presence of peroxisomes, and increased H2O2 levels, even at 28 °C. The ΔUmRrm75 mutant strains displayed a higher expression of redox-sensor UmYap1 gene and increased catalase activity than the parental strains. Our data show that deletion of the UmRrm75 gene results in higher levels of H2O2, increased melanin content, and abiotic stress sensitivity.

Modification of AtGRDP1 gene expression affects silique and seed development in Arabidopsis thaliana.

Glycine Rich Proteins (GRPs) are induced at different developmental stages and in specific plant tissues. Recently, we described a novel Arabidopsis gene encoding a short glycine-rich domain protein (AtGRDP1). This gene is involved in abiotic stress responsiveness; the Atgrdp1-null mutant seeds were more sensitive to stress, while the opposite phenotype was achieved by AtGRDP1 overexpression. In this study, we analyzed the phenotype of the fruits produced by Arabidopsis Atgrdp1 mutants and 35S::AtGRDP1 overexpression lines. Our analyses revealed important changes in silique length, seed number, seed weight and morphology in the analyzed lines. In particular, Atgrdp1 mutant lines exhibited several defects including short siliques, a diminished number of seeds per silique, and a reduction in seed size and weight as compared to Col-0. The overexpression of the AtGRDP1 gene also generated phenotypes with alterations in size of silique, number of seeds per silique, and size and weight of the seed. In addition, the expression analysis of AtGRDP1 gene showed that it was expressed in floral and fruit organs, with the highest expression level in mature siliques. The alterations in the siliques and seeds traits in the Atgrdp1 mutant line, as well as the phenotypes observed in AtGRDP1 overexpression lines, suggest a role of the AtGRDP1 gene in the Arabidopsis fruit development.

Simultaneous Silencing of Two Arginine Decarboxylase Genes Alters Development in Arabidopsis.

Polyamines (PAs) are small aliphatic polycations that are found ubiquitously in all organisms. In plants, PAs are involved in diverse biological processes such as growth, development, and stress responses. In Arabidopsis thaliana, the arginine decarboxylase enzymes (ADC1 and 2) catalyze the first step of PA biosynthesis. For a better understanding of PA biological functions, mutants in PA biosynthesis have been generated; however, the double adc1/adc2 mutant is not viable in A. thaliana. In this study, we generated non-lethal A. thaliana lines through an artificial microRNA that simultaneously silenced the two ADC genes (amiR:ADC). The generated transgenic lines (amiR:ADC-L1 and -L2) showed reduced AtADC1 and AtADC2 transcript levels. For further analyses the amiR:ADC-L2 line was selected. We found that the amiR:ADC-L2 line showed a significant decrease of their PA levels. The co-silencing revealed a stunted growth in A. thaliana seedlings, plantlets and delay in its flowering rate; these phenotypes were reverted with PA treatment. In addition, amiR:ADC-L2 plants displayed two seed phenotypes, such as yellow and brownish seeds. The yellow mutant seeds were smaller than adc1, adc2 mutants and wild type seeds; however, the brownish were the smallest seeds with arrested embryos at the torpedo stage. These data reinforce the importance of PA homeostasis in the plant development processes.

Arabidopsis AtDjA3 Null Mutant Shows Increased Sensitivity to Abscisic Acid, Salt, and Osmotic Stress in Germination and Post-germination Stages.

DnaJ proteins are essential co-chaperones involved in abiotic and biotic stress responses. Arabidopsis AtDjA3 gene encodes a molecular co-chaperone of 420 amino acids, which belongs to the J-protein family. In this study, we report the functional characterization of the AtDjA3 gene using the Arabidopsis knockout line designated j3 and the 35S::AtDjA3 overexpression lines. Loss of AtDjA3 function was associated with small seed production. In fact, j3 mutant seeds showed a reduction of 24% in seed weight compared to Col-0 seeds. Expression analysis showed that the AtDjA3 gene was modulated in response to NaCl, glucose, and abscisic acid (ABA). The j3 line had increased sensitivity to NaCl and glucose treatments in the germination and cotyledon development in comparison to parental Col-0. Furthermore, the j3 mutant line exhibited higher ABA sensitivity in comparison to parental Col-0 and 35S::AtDjA3 overexpression lines. In addition, we examined the expression of ABI3 gene, which is a central regulator in ABA signaling, in j3 mutant and 35S::AtDjA3 overexpression lines. Under 5 µM ABA treatment at 24 h, j3 mutant seedlings displayed higher ABI3 expression, whereas in 35S::AtDjA3 overexpression lines, ABI3 gene expression was repressed. Taken together, these results demonstrate that the AtDjA3 gene is involved in seed development and abiotic stress tolerance.

A dehydrin-dehydrin interaction: the case of SK3 from Opuntia streptacantha.

Dehydrins belongs to a large group of highly hydrophilic proteins known as Late Embryogenesis Abundant (LEA) proteins. It is well known that dehydrins are intrinsically disordered plant proteins that accumulate during the late stages of embryogenesis and in response to abiotic stresses; however, the molecular mechanisms by which their functions are carried out are still unclear. We have previously reported that transgenic Arabidopsis plants overexpressing an Opuntia streptacantha SK3 dehydrin (OpsDHN1) show enhanced tolerance to freezing stress. Herein, we show using a split-ubiquitin yeast two-hybrid system that OpsDHN1 dimerizes. We found that the deletion of regions containing K-segments and the histidine-rich region in the OpsDHN1 protein affects dimer formation. Not surprisingly, in silico protein sequence analysis suggests that OpsDHN1 is an intrinsically disordered protein, an observation that was confirmed by circular dichroism and gel filtration of the recombinantly expressed protein. The addition of zinc triggered the association of recombinantly expressed OpsDHN1 protein, likely through its histidine-rich motif. These data brings new insights about the molecular mechanism of the OpsDHN1 SK3-dehydrin.

A maize spermine synthase 1 PEST sequence fused to the GUS reporter protein facilitates proteolytic degradation.

Polyamines are low molecular weight aliphatic compounds involved in various biochemical, cellular and physiological processes in all organisms. In plants, genes involved in polyamine biosynthesis and catabolism are regulated at transcriptional, translational, and posttranslational level. In this research, we focused on the characterization of a PEST sequence (rich in proline, glutamic acid, serine, and threonine) of the maize spermine synthase 1 (ZmSPMS1). To this aim, 123 bp encoding 40 amino acids of the C-terminal region of the ZmSPMS1 enzyme containing the PEST sequence were fused to the GUS reporter gene. This fusion was evaluated in Arabidopsis thaliana transgenic lines and onion monolayers transient expression system. The ZmSPMS1 PEST sequence leads to specific degradation of the GUS reporter protein. It is suggested that the 26S proteasome may be involved in GUS::PEST fusion degradation in both onion and Arabidopsis. The PEST sequences appear to be present in plant spermine synthases, mainly in monocots.

Overexpression of AtGRDP2, a novel glycine-rich domain protein, accelerates plant growth and improves stress tolerance.

Proteins with glycine-rich signatures have been reported in a wide variety of organisms including plants, mammalians, fungi, and bacteria. Plant glycine-rich protein genes exhibit developmental and tissue-specific expression patterns. Herein, we present the characterization of the AtGRDP2 gene using Arabidopsis null and knockdown mutants and, Arabidopsis and lettuce over-expression lines. AtGRDP2 encodes a short glycine-rich domain protein, containing a DUF1399 domain and a putative RNA recognition motif (RRM). AtGRDP2 transcript is mainly expressed in Arabidopsis floral organs, and its deregulation in Arabidopsis Atgrdp2 mutants and 35S::AtGRDP2 over-expression lines produces alterations in development. The 35S::AtGRDP2 over-expression lines grow faster than the WT, while the Atgrdp2 mutants have a delay in growth and development. The over-expression lines accumulate higher levels of indole-3-acetic acid and, have alterations in the expression pattern of ARF6, ARF8, and miR167 regulators of floral development and auxin signaling. Under salt stress conditions, 35S::AtGRDP2 over-expression lines displayed higher tolerance and increased expression of stress marker genes. Likewise, transgenic lettuce plants over-expressing the AtGRDP2 gene manifest increased growth rate and early flowering time. Our data reveal an important role for AtGRDP2 in Arabidopsis development and stress response, and suggest a connection between AtGRDP2 and auxin signaling.

Further evidence from the effect of fungi on breaking Opuntia seed dormancy.

Recently, we found that fungi are involved in breaking seed dormancy of Opuntia streptacantha, and that the effect of fungi on seeds is species-specific. However, the effect of fungi on seed germination from other Opuntia spp has not been evaluated. Thus, we evaluated the effect of four fungal species (Penicillium chrysogenum, Phoma sp., Trichoderma harzianum, Trichoderma koningii) on the germination of Opuntia leucotricha, an abundant species in the Chihuahuan Desert, Mexico. We found that seeds inoculated with the four fungal species had higher germination than control seeds. Trichoderma spp. were the most effective. Our results strongly indicate that fungi are involved in breaking seed dormancy of O. leucotricha. Thus, we suggest that these fungi could promote seed germination from other Opuntia species.

Evaluación de un método rápido para la detección de niveles elevados de lipoproteína (A): Aubiodot LP (A) / Evaluation of a fast method for the detection of elevated levels of lipoprotein (A): AuBioDOT Lp(A)

La lipoproteina (a) [Lp (a)] ha sido identificada como un factor de riesgo independiente de enfermedad vascular ateroesclerótica (arteriocoronaria, cerebrovascular y vascular periférica), por lo que su determinación ha cobrado gran interés en los últimos años. En este trabajo se describen los resultados obtenidos con el uso de un inmunoensayo visual para la determinación de Lp(a): AuBioDOT tm Lp(a) en comparación con un ELISA comercial: BioSCREEN tm Lp(a) (ambos desarrollados en el CIGB; Heber Biotec S. A). El AuBioDOT tm Lp(a) es un ensayo sencillo y rápido; la correlación obtenida con respecto al BioSCREEN fue de r=0,987; la sensibilidad de 88,8 porciento y la especificidad de 100 porciento. En las 100 muestras estudiadas, la frecuencia de distribución de las concentraciones de Lp(a) mostró una desviación típica hacia la derecha similar a la reportada en otras poblaciones. Este estudio permitió considerar la utilidad del AuBioDOT tm Lp(a) como un método de pesquizaje para identificar riesgo individual de forma rápida y económica

Evaluación de un método rápido para la detección de niveles elevados de lipoproteína (A): Aubiodot LP (A) / Evaluation of a fast method for the detection of elevated levels of lipoprotein (A): AuBioDOT Lp(A)

La lipoproteina (a) [Lp (a)] ha sido identificada como un factor de riesgo independiente de enfermedad vascular ateroesclerótica (arteriocoronaria, cerebrovascular y vascular periférica), por lo que su determinación ha cobrado gran interés en los últimos años. En este trabajo se describen los resultados obtenidos con el uso de un inmunoensayo visual para la determinación de Lp(a): AuBioDOT tm Lp(a) en comparación con un ELISA comercial: BioSCREEN tm Lp(a) (ambos desarrollados en el CIGB; Heber Biotec S. A). El AuBioDOT tm Lp(a) es un ensayo sencillo y rápido; la correlación obtenida con respecto al BioSCREEN fue de r=0,987; la sensibilidad de 88,8 porciento y la especificidad de 100 porciento. En las 100 muestras estudiadas, la frecuencia de distribución de las concentraciones de Lp(a) mostró una desviación típica hacia la derecha similar a la reportada en otras poblaciones. Este estudio permitió considerar la utilidad del AuBioDOT tm Lp(a) como un método de pesquizaje para identificar riesgo individual de forma rápida y económica (AU)

Comparación de 3 métodos empleados para el control de calidad de medios de cultivo sólidos utilizados en microbiología de alimentos / Comparison of 3 methods employed in the quality control of solid culture media in foot microbiology

El objetivo de este estudio fue comparar 3 métodos utilizados en el control de calidad de medios de cultivo: a) el método original de Miles-Misra, b) el ecométrico y c) el de estrías. Para ello se evaluaron la productividad y la selectividad de 6 medios sólidos de cultivo usados para el aislamiento de Salmonella spp. y Shigella spp. Los resultados que se obtuvieron al comparar los 3 métodos mediante la prueba de chi-cuadrado demuestran que existe diferencia (p < 0,05) entre el método de estrías y los otros 2 en lo referente a la productividad, pero no en cuanto a la selectividad. De los métodos ensayados, el ecométrico resultó el de más fácil y rápida ejecución

Comparación de 3 métodos empleados para el control de calidad de medios de cultivo sólidos utilizados en microbiología de alimentos / Comparison of 3 methods employed in the quality control of solid culture media in foot microbiology

El objetivo de este estudio fue comparar 3 métodos utilizados en el control de calidad de medios de cultivo: a) el método original de Miles-Misra, b) el ecométrico y c) el de estrías. Para ello se evaluaron la productividad y la selectividad de 6 medios sólidos de cultivo usados para el aislamiento de Salmonella spp. y Shigella spp. Los resultados que se obtuvieron al comparar los 3 métodos mediante la prueba de chi-cuadrado demuestran que existe diferencia (p < 0,05) entre el método de estrías y los otros 2 en lo referente a la productividad, pero no en cuanto a la selectividad. De los métodos ensayados, el ecométrico resultó el de más fácil y rápida ejecución

Comparación de tres métodos empleados para el control de calidad de medios de cultivo sólido / Comparison of three methods employed in tue quality control of solid culture media

El objetivo de este estudio fue comparar tres métodos utilizados en el control de calidad de medios de cultivo: a)el método original de Miles-Mirsa; b)el ecométrico y c)el método de estrías. Para comparar estos métodos, se evaluaron la productividad (crecimiento de un microorganismo que habitualmente se desarrolla en un medio de cultivo) y la selectividad (supresión del crecimiento de un microorganismo, que se espera sea inhibido en un medio de cultivo) de seis medios sólidos de cultivo usados para el aislamiento de Salmonella spp. y Shigella spp. Los resultados que se obtuvieron al comparar los 3 métodos, mediante la prueba de Chi2, reflejan que existe diferencia significativa (p<0.05) entre el método de estrías y los otros 2 en lo referente a la productividad, no existiendo diferencia significativa entre los 3 métodos, en cuanto a selectividad. De los 3 métodos ensayados, el ecométrico resultó el de más fácil y rápida ejecución

Comparación de tres métodos empleados para el control de calidad de medios de cultivo sólido / Comparison of three methods employed in tue quality control of solid culture media

El objetivo de este estudio fue comparar tres métodos utilizados en el control de calidad de medios de cultivo: a)el método original de Miles-Mirsa; b)el ecométrico y c)el método de estrías. Para comparar estos métodos, se evaluaron la productividad (crecimiento de un microorganismo que habitualmente se desarrolla en un medio de cultivo) y la selectividad (supresión del crecimiento de un microorganismo, que se espera sea inhibido en un medio de cultivo) de seis medios sólidos de cultivo usados para el aislamiento de Salmonella spp. y Shigella spp. Los resultados que se obtuvieron al comparar los 3 métodos, mediante la prueba de Chi2, reflejan que existe diferencia significativa (p<0.05) entre el método de estrías y los otros 2 en lo referente a la productividad, no existiendo diferencia significativa entre los 3 métodos, en cuanto a selectividad. De los 3 métodos ensayados, el ecométrico resultó el de más fácil y rápida ejecución