Ciencias Agropecuarias
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Item Presencia de genes de resistencia a los antibióticos en Escherichia coli aislada de carne de pollo que se expende en el cantón de Ambato(2024-11) Gómez Aillòn Diego José; Cruz Quintana Sandra MargaritaAntimicrobial resistance is currently a public health problem in Ecuador. It seems that the indiscriminate use of antibiotics in animal production is a way for the development of this resistance. E. coli is a pathogen that affects animals and people and has developed resistance to several antibiotics in recent years. Cephalosporins and quinolones are used in broiler production and are two families of antibiotics to which strains of E. coli They have shown resistance. This resistance is mainly mediated by resistance genes such as gyrA and blaCTXM. Studies have searched for these mechanisms in E. coli strains from chicken meat, as it is one of the main meats consumed in Ecuador. The present study aimed to evaluate the antibioresistance and the presence of resistance genes of 31 Escherichia coli strains to antibiotics. Antibioresistance was carried out by the agar diffusion method and the search for resistance genes through PCR. In this way, a Kruskall Wallis test and the Mann Whitney U test were performed for the antibioresistance data, and for the genes, prevalence and a chi-square test were analyzed, with a 95% confidence interval. The results for the antibioresistance of the strains were resistant to ciprofloxacin 45.1% and ceftriaxone 25.8% and the antibiotics that provided greater susceptibility were gentamicin and amikacin with a p≤0.05. For the gyrA genes of CIP and blaCTXM of CX there were prevalence of 100% and 96.77% respectively. When comparing the difference between the origin of the sales center and the resistance gene, there was no statistical difference p≥ 0.05 in both genes. Finding resistance to antibiotics gives us a warning that the indiscriminate use of these in the country's animal production could be an important factor for this resistance. The prevalence of genes is a guide to the main resistance mechanism that could be used by E. coli, such as mutations in genes and genes that encode enzymes that provide resistance. And finally, finding antibioresistance and resistance genes in chicken meat in the Ambato canton is a warning of the possible risk of transmissibility of resistant strains that could generate resistance to antibiotics in people. However, the current data in Ecuador on this possibility is not yet being studied with the importance of the case. Therefore, studies like this open a gap for us to analyze everything that antibioresistance implies and the repercussions on public health in Ecuador.Item 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 MargaritaShigella 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.Item Evaluación de la sensibilidad a los antibióticos y presencia de genes de resistencia en Lactococcus garvieae aislado en carne de pollo que se expende en Ambato(2024-08) Chávez Romero, Anderson Xavier; Cruz Quintana, Sandra MargaritaLactococcus garvieae is a Gram-positive pathogenic bacterium, considered an emerging zoonotic pathogen, as reports of human infection are increasing. In the present research work, the antibioresistance of the L. garvieae strain and the presence of resistance genes in L. garvieae isolated from chicken meat sold in Ambato were evaluated. Sensitivity was identified using the Kirby Bauer method for the following antibiotics: Linezolid, Ceftriaxone, Amoxicillin+clavulanic acid, Lincomycin and Oxytetracycline. After obtaining results where four of the five antibiotics were resistant: Linezolid, Ceftriaxone Lincomycin and Oxytetracycline where we chose oxytetracycline, which showed the highest resistance and is the most widely used antibiotic in livestock farming. An arduous investigation was carried out to identify resistance genes, tetD and tetA, then the DNA of L. garvieae was extracted by the method of Aljanabi & Martinez modified, the PCR technique was carried out with the corresponding primers of the genes and ended with an electrophoresis where it was not identified that it has tetD and tetA genes of resistance to oxytetracycline and finally it was investigated on the molecular mechanisms of resistance of L. garvieae to the different resistant antibiotics.Item Evaluación de la presencia de los genes de resistencia a antibióticos betalactámicos y glucopéptidos en Mammaliicoccus sciuri aislado de la carne de pollo que se expende en Ambato(2024-08) Barreno Mayorga, Jessica Fernanda; Cruz Quintana, Sandra MargaritaAntibiotic resistance represents a significant public health problem due to the ability of bacteria to cause difficult-to-treat infections. The objective of this research is to detect the presence of resistance genes to beta-lactam antibiotics (amoxicillin + clavulanic acid) and glycopeptides (vancomycin) in the bacteria Mammaliicoccus sciuri isolated from chicken meat sold in Ambato. The research was carried out by collecting Mamamlicocus samples isolated from chicken meat and analyzing them in the laboratory to determine the presence of the aforementioned resistance genes, using PCR, DNA extraction and electrophoresis. Obtaining as results the presence of resistance genes in beta-lactams with an amplification of the band of 162 bp but no amplification of glycopeptides was found, which means that there are different ways for the existence of resistance. The identification and monitoring of these genes are crucial to evaluate food safety and prevent the spread of resistant bacteria in the final food chain.Item Evaluación de la sensibilidad a los antibióticos y factores de virulencia de bacterias Gram negativas aisladas de la carne de pollo que se expenden en el cantón de Ambato (Comamonas kerstersii, Aeromonas veronii, Pseudomonas aeruginosa)(2024-02) Ramírez Pérez, Juan José; Cruz Quintana, Sandra MargaritaThe following research work was developed in the Laboratories of the Technical University of Ambato, with the objective of evaluating the sensitivity to antibiotics and virulence factors of the following bacteria: Comamonas kerstersii, Aeromonas veronii, and Pseudomonas aeruginosa, isolated from meat of chicken that is spent in the Ambato canton. We worked with 6 samples, carrying out the management of the experiment in three phases. The statistical method used was the Kolmogorov Smirov method to determine if there is a normal distribution. Demonstrating the results, the following data: Pseudomonas aeruginosa and Comamonas kerstersii have greater sensitivity to the antibiotics used, while Aeromonas veronii showed resistance. The molecular mechanisms of resistance vary according to the type of bacteria and the antibiotic. Finally, as a defense mechanism, bacteria develop virulence factors to evade the response of the body's immune system. Keywords: Comamonas kerstersii, Aeromonas veronii, and Pseudomonas aeruginosa, sensitivity, resistance, antibiotic, bacteria, virulence factors.Item Perfiles fenotípicos de resistencia a antibióticos en aislados de Escherichia coli de origen canino de la ciudad de Ambato(2021-03) Robalino Proaño, David Guillermo; Calero Cáceres, William RicardoCurrently, antibiotic resistance crisis is a global concern, both in human and veterinary medicine. The uncontrolled evolution of the resistance mechanisms in bacteria has had a negative influence on effective therapeutic options. This research has focused on the enterobacterium Escherichia coli, focused on the detection of the extended espectrum beta-lactamases (ESBL) and AmpC type beta-lactamases, which represent variants with resistance mechanisms of great clinical impact in Gram negative bacteria. In Ecuador, few epidemiological data are available on E. coli producing ESBL and AmpC in animals. In the present study, the phenotypic profiles of resistance to antibiotics were evaluated in a collection of isolates of E. coli of canine origin from the city of Ambato, using the Kirby & Bauer disk diffusion method, detecting that 72.2% (57/79) of isolates have an ESBL phenotype and 81% (64/79) of isolates with manifestation of the AmpC phenotype. The percentages of resistance for the evaluated antibiotics was: Ampicillin 100% (79/79), Vancomycin 100% (79/79), Cefotaxime 98.7% (78/79), Erythromycin 98.7% (78/79), Ceftriaxone 97.5% (77 / 79); and phenotypic sensitivity patterns for antimicrobials such as: Meropenem 98.7% (78/79), Imipenem 96.2% (76/79) Piperacillin / Tazobactam 84.8% (67/79), Cefoxitin 83.5% (66/79), and Amikacin 82.3% (65/79). The patterns of bacterial resistance detected and the differences between the origin of the isolates will allow to use this background information for retrospective studies of antimicrobial resistance.Item Persistencia de bacterias entéricas resistentes y genes de resistencia a antibióticos en sustratos suplementados con gallinaza comercial y de compostaje tradicional(2021-01) Bohórquez Pucha, Jandry David; Calero Cáceres, William RicardoThe application of animal manure (fresh or composted) represents a common practice. This practice favors the increasing of organic matter into soils at reduced costs. The efficient use of the animal residues supporting the recycling of organic matter and nutrients. Compost practices transforms efficiently and safely animal manure into materials suitable for use into agricultural soils. However, the application of traditional practices to compost fertilizers, consisting of simple drying of the animal manure and later applying it directly to the soil is common. The high levels of enteric bacteria present in these matrices may represent a pathway for the spread of pathogenic organisms, which can potentially integrate within the food chain. For this reason, the persistence of enteric bacteria (heterotrophic bacteria, E. coli, coliforms) resistant to antibiotics and the persistence of antibiotic resistance genes were evaluated in soils supplemented with two types of fertilizer (compost of animal origin traditionally composted and compost of animal origin processed by the industry) during 111 days; determining that the application of these fertilizers notably increases the densities of resistant enteric bacteria (ARBs) and antibiotic resistance genes (ARGs) in soils. These pollutants have a high persistence over time, which suggests that the application of fertilizers of animal origin, especially when they do not receive appropriate treatment, may represent a pathway for the spread of antibiotic resistance determinants throughout the chain. fooItem 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 RicardoIn 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).Item Efecto de la aplicación de gallinaza de compostaje tradicional y comercial sobre las densidades de bacterias resistentes y genes de resistencia a antibióticos en cultivo de rábano (Raphanus sativus) y lechuga (Lactuca sativa)(2020-09) Cruz Morales, Carla Marisol; Calero Cáceres, William RicardoPoultry manure is traditionally used as a good source of nutrients and organic matter in agricultural soils, especially in organic-farming systems. However, these materials can cause adverse effects on general soil conditions, since they contain high densities of potentially pathogenic enteric bacteria; such as antibiotic resistant bacteria (ARBs) and their corresponding antibiotic resistance genes (ARGs). The use of these materials may represent a probable route of dissemination of pathogenic microorganisms and their determinants through the food chain. This thesis is part of the project "EVALUACIÓN DE LA DISEMINACIÓN AMBIENTAL DE GENES DE RESISTENCIA A ANTIBIÓTICOS POR MEDIO DEL ESTIÉRCOL DE GALLINA" (HCU 1752-CU-P-2019). The aim of this thesis is the evaluation of the effect of the addition of traditional and commercial composting on the densities of ARBs and ARGs in vegetables (lettuce and radish). The virulence and resistance mechanisms of the detected E. coli isolates were evaluated. The results suggest that traditional composting chicken manure influences to a greater extent the spread of ARBs and ARGs in relation to commercial chicken manure. The E. coli isolates presented an antibiotic multiresistance profile. The transconjugation experiments suggest the mechanisms of antibiotic resistance of these bacteria were found encoded in chromosomes and not in plasmids. On the other hand, the qPCR technique was used to detect ARGs, which showed very high levels of detection for sul1 and blaTEM and low levels of detection to qnrS, tetW, ermB and 16S rDNA. The dissemination of ARBs and ARGs from traditional and commercial poultry manure to food is plausible, representing this a potential route of dissemination of antibiotic resistance determinants through the food chain.Item Análisis bioinformático de cuatro secuencias de genoma completo de Salmonella entérica de origen avícola(2020-03-19) Villacis Grijalva, Joyce Elizabeth; Calero Cáceres, William RicardoThe application of molecular epidemiological tools applied to microbiology provides valuable evidence to elucidate the origin of clinical outbreaks. Additionally, provides information that supports the opportune intervention and takes of control measures. Nowadays, the raising of new omics technologies, as new generation sequencing (NGS) of complete genomes and the development of bioinformatics tools are improving the knowledge and the understanding of the microbiology. The implementation of these technological tools in microbiological studies is allowing to study in real-time and low cost the evolution and dissemination of new pathogens that are circulating across our geographical area. Salmonella enterica represents one of the most important pathogens that deserves special attention, considering its implications in clinical and productive sectors. Considering these reasons, it is important the realization of epidemiological studies using bioinformatic tools that allow analyze the origin, dissemination, virulence mechanisms and resistance genotypes. In this study, four S. enterica serovar Infantis and Kentucky from layer poultry origin obtained in Tungurahua and Cotopaxi were analyzed through WGS and the bioinformatic tools of Center of Genomic Epidemiology (University of Denmark) and BaseSpace (Illumina Inc). All the strains were categorized as human pathogens. According to their sequence-type, it belongs to the ST32 (Infantis) and ST152 (Kentucky). The strains harbor a plethora of antibiotic resistance genes. It is worth noting the presence of the beta-lactamases blaCTX-M-148 and blaCTX-M-65, which show an emerging raising in clinical and animal origin isolates around the world. Finally, our sequences were compared with sequences of analogous bacteria from different origins and geographical locations through phylogenetic trees. Our sequences are related to clinical isolates from the United States, suggesting that their share a common ancestor.