Unidad Posgrado Facultad Ingeniería Agronómica

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    Presencia de genes de resistencia a los antibióticos en Shigella spp. aislada de carne de pollo que se expende en el cantón de Ambato.
    (2024-11) Pazmiño Orozco Andrés Sebastián; Cruz Quintana Sandra Margarita
    Shigella spp. is a common causal agent of diarrheal diseases around the world. The treatment of choice for shigellosis is the administration of antibiotics. However, the resistance that Shigella spp. has developed to these molecules poses a major challenge in the need to find effective treatment alternatives. Transmission of Shigella spp. is via the fecal-oral route, however, infection can result from the ingestion of contaminated food where poor hygiene during handling can be considered a risk factor for the occurrence of disease. Likewise, unhygienic conditions during the slaughter of animals could constitute one of the main sources of contamination of meat for human consumption. In this research, we start from previous studies where, from samples of chicken meat taken from points of sale and slaughterhouses in Ambato, 17 strains of Shigella spp. were isolated and molecularly identified and some of them, showed marked resitance mainly to two antibiotics: amoxicillin-clavulanate (AMC) and ciprofloxacin (CIP). The aim of this investigation was to verify the presence of a resistance gene for each of the antibiotics described above. For AMC, the blaTEM gene was searched for, which encodes for class A ESBL (extended spectrum β-lactamases), finding a prevalence of 23.53%, while for CIP, the gyrA gene was searched for, which encodes for the A subunits of DNA gyrase, finding a prevalence of 100%. One of the resistance mechanisms for AMC would be the production of TEM-like ESBLs, while specific mutations in a small region near the start of the gyrA gene, called the quinolone resistance determining region (QRDR), have been widely linked to CIP resistance in Enterobacteriaceae.
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    Aislamiento, caracterización cultural, morfológica, patogénica e identificación de genes AVR en Cladosporium fulvum Cooke.
    (2023-12) Sánchez Ortiz, Aldo Martin; Leiva Mora, Michel
    Gray mold caused by Cladosporium fulvum was described by Cooke in 1883, which develops in nightshades, specifically in tomato crops, causing damage from the youngest leaves to the top of the plant. The objective of this research was to "Isolate and characterize culturally, morphologically and pathogenically monosporic isolates of Cladosporium fulvum" obtained from signs of gray mold on Solanum lycopersicum leaves to identify the presence or absence of Avr genes in the cantons of the province of Tungurahua (Ambato, Baños, Cevallos, Mocha, Patate, Pelileo, Píllaro, Tisaleo). For isolation, the leaf printing method was applied in potato dextrose (PDA) culture medium with gentamicin sulfate, to describe the cultural and morphological characteristics, the microculture method was used accompanied by the observation of fungal structures under an optical microscope. of transmitted light. In the pathogenic characterization, the isolates of C. fulvum were activated The conidia were counted in the Neubauer chamber of the differential cultivars previously sown on substrates and the inoculum was applied with a manual sprayer. For amplification, DNA extraction and lyophilization of each of the isolates was carried out prior to development. of conventional PCR with two denaturations at 94°C with different cycles and an annealing at 55°C and 34 cycles with a final extension of 72°C. Obtaining that in the 8 cantons of the province of Tungurahua they all showed olive green colors on the obverse, while on the back it was black, with a superficial elevation, plush texture and irregular shape, lobed edges and in some isolates there was pigmentation and perspiration liquid, the mycelial growth in the colonies was obtained with a length of 5.93 µm, width 2.8 µm, hyphae 5.37 µm and conidiophores 32.97 µm average values. In the pathogenic characterization it was evident that the degree of affectation 1 represented between 1 to 5% of the surface of leaves with signs of C. fulvum, while 2 varied from 6 to 20% in the differential cultivars (Cf0-Cf2- Cf4- Cf5-Cf6), finally in the detection of the presence or absence of genes, the presence of the genes Avr2, Avr4e, Ecp2, Ecp4 and Ecp5 and total absence of the genes Avr4, Avr9 and Ecp1 were observed. Based on the results and the tests carried out, it was possible to create bases for the selection of resistance genes for the production of S. lycopersicum hybrids in the province of Tungurahua.
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    Presencia de enterobacterias portadoras de genes de resistencia a antibióticos emergentes procedentes de aguas de riego y superficiales del Ecuador, año 2019.
    (2020-09) Mendoza León, David Israel; Calero Cáceres, William Ricardo
    In order to assess the degree of biological pollution of water in the country, the aim of this researching was the identification of bacteria resistant to emerging antibiotics from surface waters of 5 provinces of Ecuador. The sampling points for the analysis were determined based on a space-temporal study, based on historical data by the National Institute for Public Health Research (INSPI) based on to the presence of population, hospitals, crops, animal production and industries. The collection of samples was carried out from rivers, irrigation canals, collection points. About 71 samples were taken at strategic points based on US EPA-600 / 4- 79-0120 "Methods for the Collection and Analysis of Water and Waste", of which 40 (24 from the river and 16 from the irrigation canal ) corresponded to water and 31 samples (16 from the river and 15 from the irrigation canal) corresponded to sediments. Seeds were performed on Chromocult® and MacConkey agar enriched with 2 µg of Ceftriaxone. From the samples, the indicators of faecal contamination were E. coli and total coliforms, thus E. coli and ceftriaxone resistant total coliforms (2 µg / mL). 10 genes (mcr-1 mcr-2 mcr-3 mcr-4 mcr-5, blaKPC, blaNDM, blaIMP and blaVIM) were detected for antibiotic resistance in the PCR process, byconfirming the amplification they were identified and identified 9 positive isolates to emerging antibiotic resistance genes (8 for mcr-1 and, 1 for blaKPC).