Tesis Medicina Veterinaria
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Item Evaluación de la sensibilidad antibiótica y presencia de genes de resistencia en Enterococcus gallinarum aislado en carne de pollo en Ambato(2024-08) Villacis Gamboa, David Alexander; Cruz Quintana, Sandra MargaritaEnterococcus gallinarum is a Gram-positive bacterium that grows in short chains and can be found in the gastrointestinal tract of animals and humans at temperatures ranging from 10 - 37ºC. The aim of the study was to evaluate the antibiotic sensitivity and presence of resistance genes in Enterococcus gallinarum isolated from chicken meat in Ambato. The Kirby Bauer method with antibiotic discs was used to evaluate the sensitivity and resistance to vancomycin, erythromycin, ciprofloxacin, amoxicillin + clavulanic acid and trimethopin + sulfamethasone. The antibiotic chosen to detect resistance genes was vancomycin by DNA extraction, PCR and electrophoresis. PCR primers VanA F and VanA R were used to amplify a band of 732 base pairs. Resistance to vancomycin, erythromycin, ciprofloxacin and sensitivity to amoxicillin + clavulanic acid and trimethopin + sulfamethasone was shown. No vancomycin resistance genes were detected and the main molecular mechanisms of resistance of Enterococcus gallinarum to vancomycin were investigated as efflux pumps, resistance genes and target site modification. It was concluded that Enterococcus gallinarum from chicken meat sold in the canton of Ambato is sensitive to clavulanic acid and trimethopin + sulfamethasone and resistant to vancomycin, erythromycin and ciprofloxacin. To vancomycin it does not present resistance genes, its main resistance mechanisms are resistance genes, efflux pumps, modification of the target point.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 antibiorresistencia en bacterias grampositivas aisladas en carne de pollo que se expende en el cantón Ambato, provincia de Tungurahua(2024-02) Velastegui Viteri, Cristian David; Cruz Quintana, Sandra MargaritaThe present investigation was carried out with the main purpose of evaluating the antibacterial resistance in Gram positive bacteria (Vagococcus lutrae, Mammaliicoccus sciuri and Kurthia gibsonii) isolated in chicken meat sold in Ambato Canton, province of Tungurahua, because bacterial resistance to antibiotics is a specific aspect of the natural evolution of bacteria, The study was carried out with strains of (Vagococcus lutrae, Mammaliicococcus sciuri and Kurthia gibsonii) that were isolated and molecularly identified from chicken meat sold in the canton of Ambato from previous investigations, which are kept in the Laboratory of Microbiology and Molecular Biology of the Faculty of Agricultural Sciences of the Technical University of Ambato. It was found that there is the presence of antibioresistance in gram-positive bacteria, specifically in strains of Vagococcus lutrae, Mammaliicoccus sciuri and Kurthia gibsonii, isolated from samples of chicken meat marketed in the Ambato Canton, province of Tungurahua. Likewise, the results obtained by the agar diffusion method revealed significant patterns of antibiotic resistance in the Gram-positive bacteria studied. Resistance profiles against various antibiotics used in both Veterinary and Human Medicine were identified, highlighting the importance of addressing resistance in an interdisciplinary context and the analysis of virulence factors in strains of Vagococcus lutrae, Mammaliicococcus sciuri and Kurthia gibsonii provided valuable information on the possible risks associated with these bacteria in chicken meat. Keywords: EVALUATION, ANTIBIORRESISTANCE, BACTERIA, GRAM POSITIVE, CHICKEN MEAT, AMBATO, TUNGURAHUA.Item Evaluación de antibiorresistencia de cepas de Shigella spp aisladas en carne de pollo en la ciudad de Ambato, provincia de Tungurahua(2024-02) Soto Villacis, Joselyn Anabel; Cruz Quintana, Sandra MargaritaShigella spp exhibits remarkably high and highly developed antibiotic resistance mechanisms, which constitutes a global challenge for public health. One of the main routes of transmission of this resistance is observed in foods of animal origin, highlighting that the lack of hygiene and sanitary control in slaughter centers contributes to its spread. The objective of this research was to evaluate the antibioresistance of Shigella spp strains isolated from chicken meat in the city of Ambato, Tungurahua Province. We worked with 17 strains of Shigella spp subjected to two phases of research. In the first phase, the Kirby Bauer phenotypic method (diskplate) was used to determine the resistance, intermediate or susceptibility of the strains to a group of drugs that includes Azithromycin (AZM), Gentamicin (CN), Ceftriaxone (CRO), Amoxicillin + clavulanic acid (AMC) and Ciprofloxacin (CIP). The results were analyzed using the Kruskal Wallis test, complemented by the Mann Whitney U test. A resistance of 82.4% was obtained for CIP, 64.7% for AMC, 29.4% for CRO, 23.5% for CN and 5.9% for AZM. In the second phase, the Minimum Inhibitory Concentration (MIC) of the strains that showed sensitivity in phase 1 to the aforementioned antibiotics was determined. The results were analyzed descriptively using curves, establishing the MICs for AZM 160 μg/ml, CN 10 μg/ml, AMC 160 μg/ml, CRO 1.25 μg/ml and CIP 20 μg/ml, following the CLSI cut-off points in 2016. It was considered essential to investigate the resistance mechanisms exhibited by Shigella spp. First, we focused on fluoroquinolones, as this group showed significant resistance due to the presence of chromosomal mutations. In addition, resistance related to the production of ESBL was observed for beta-lactams, as well as the alteration of the target site present in aminoglycosides, the existence of genes such as mphA or ermB in macrolides. Keywords: Shigella spp, antibioresistance, MIC, mechanisms, antibioticsItem 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 Evaluación de antibiorresistencia de cepas de Proteus spp aisladas en carne de pollo en la ciudad de Ambato, provincia de Tungurahua(2023-09) Coka Escobar, Carolina Alejandra; Cruz Quintana, Sandra MargaritaProteus spp is one of the most sensitive genera within the enterobacteria, it maintains sensitivity to aminoglycosides, beta-lactams and fluoroquinolones, however, due to the frequent and imprudent use of these antibiotics, an increase in the cut-off points for minimum inhibitory concentration has been observed which are statistically significant, this is due to the different mechanisms of resistance that the bacteria present and which represent a relevant problem in public health. In this research work, the antibioresistance of 18 strains of Proteus spp. was evaluated using the Kirby Bauer method for the following group of antibiotics: Amikacin, Gentamicin, Amoxicillin + clavulanic acid, Ceftriaxone, Ciprofloxacin, the results obtained were analyzed using the Kruskal Wallis test complemented with the Mann Whitney U test, obtaining results of antibiotic percentage of: Ciprofloxacin: 27.7%, Ceftriaxone:16.6%, Amoxicillin + clavulanic acid: 22.2% , Gentamicin and Amikacin: 0%. For the second phase, the cut-off points established by CLSI (The Clinical & Laboratory Standards Institute, 2023) to evaluate the minimum inhibitory concentration, however, the inhibition curves increased with the following results: Amikacin (AK): 18-20 μg/ml Gentamicin (CN): 18-22 μg/ml Ciprofloxacin (CIP): 19-21 μg/ml Ceftriaxone (CRO):18-22 μg/ml Amoxicillin + Àc. Clavulanic acid (AMC): 28-33 μg/ml. Therefore, it was considered essential to study the mechanisms of resistance presented by Proteus spp, firstly towards fluoroquinolones, which was one of the groups with the highest resistance due to the presence of chromosomal mutations, the production of BLEE for beta-lactams and alteration of the target site or mutations of hydroxyl groups and aminos present in aminoglycosides.Item Determinación de antibiorresistencia de cepas de Escherichia coli aisladas en carne de pollo en la ciudad de Ambato, provincia de Tungurahua(2023-09) Castro Velasco, Katerin Anahí; Cruz Quintana, Sandra MargaritaEscherichia coli presents significantly high and well-developed resistance mechanisms towards antibiotics, representing a worldwide problem for public health, one of its transmission routes is in food of animal origin, noting that the dissemination is facilitated by poor hygiene and Sanitary control in slaughterhouses. The objective of the present investigation was to determine the antibioresistance of Escherichia coli strains isolated in chicken meat in the city of Ambato, Tungurahua Province. We worked with a total of 31 E.coli strains subjected to two research phases, the first to establish the Resistance, Intermediate or Sensitivity of the strains to the group of antibiotics: Amikacin, Gentamicin, Amoxicillin + clavulanic acid, Ceftriaxone, Ciprofloxacin through of the Kirby Bauer phenotypic method (Disc-plaque), the results were subjected to the Kruskal Wallis test complemented with the Mann Whitney U test, obtaining a CIP Resistance: 45%, CRO: 25.8%, AMC: 9.8%. , CN and AK: 0%, following CLSI 2023 cut-off points. In the second phase, the MIC (Minimum Inhibitory Concentration) of the resulting strains sensitive to the group of antibiotics in phase 1 was determined, the results were analyzed descriptively through of curves establishing the MIC of AK: 18-20 μg/ml CN: 18-22 μg/ml CIP: 19-21 μg/ml CRO:18- 22 μg/ml AMC: 28-33 μg/ml, following points of CLSI 2023 cutoff. The main resistance mechanisms of Escherichia coli to beta-lactams are beta-lactamases, to aminoglycosides mutations in amino and hydroxyl groups and alteration of target sites and in fluoroquinolones chromosomal mutations in DNA gyrase and topoisomerase occur, all of these methods developed by E.coli block the action of drugs. In conclusion, it was determined that E. coli shows a marked resistance to antibiotics thanks to resistance methods that the bacteria presents through enzymes and mutations.Item Identificación molecular de aislados bacterianos contaminantes de carne de pollo (Gallus gallus) expendida en puntos de venta del cantón Ambato(2023-03) Escobar Aguilar, Solange Belén; Cruz Quintana, SandraFood of animal origin is exposed to several contamination factors in the production chain. Based on this argument, the objective of this research was the molecular identification of bacterial isolates contaminating chicken meat (Gallus gallus) sold in points of sale in the Ambato canton. The methodology started with 130 bacterial isolates, continued with the extraction of DNA, evaluating its quality by means of spectrophotometry with absorbance of 260/280 nm, determining its purity. For PCR using the 16S ribosomal DNA region, the universal primers 27F and 1492 R were used, and then electrophoresis was performed. The size of the bands was 1 500 base pairs (bp), the samples were sequenced and the identity of the processed bacteria was obtained, which were: Proteus mirabilis (36.09%), Escherichia coli (30.83%), Shigella sonnei (7.52%), Shigella flexneri (3.76%), Shigella dysenteriae (1.5%), Shigella sp. (0. 75%), Salmonella enterica (1.5%), Escherichia fergusonni (5.26%), Mammaliicoccus sciuri (2.26%), Enterobacter cloacae (1.5%), Proteus vulgaris (1.5%), Pseudescherichia vulneris (1.5%), Kurthia gibsonii (1.5%), Proteus sp. (0.75%), Comamonas kerstersii (0.75%), Cronobacter sakazakii (0.75%), Vagococcus lutrae (0.75%), Escherichia marmotae (0.75%) and Klebsiella variicola (0.75%). Finally, to compare the sequences deposited in the GenBank database, the content of Guanines + Cytokines, which are related to pathogenic islands, was taken into account; the bacterium with the highest content was Cronobacter sakazakii with 59.6%. In conclusion, the raw chicken meat sold in this territory contains a high index of microbiological contamination, demonstrating that one of the causes for the development of foodborne diseases (FBD) is the inadequate handling of the product, thus representing a serious problem for public health.Item Frecuencia de Campylobacter spp en muestras de carne de pollo procedentes de plantas de faenamiento que suministran al cantón Ambato(2023-03) Toapanta Toapanta, Jeniffer Vanesa; Cruz Quintana, SandraCampylobacter spp. It is considered one of the most important meat contaminants as it is the cause of most foodborne diseases (ETAs) in humans, its main route of transmission is through contaminated food of animal origin. The slaughtering process plays a very important role in the dissemination of this bacterium, in this sense the slaughtering plants must comply with all hygienic-sanitary regulations to avoid the presence of Campylobacter spp. in chicken meat. The objective of this study was to determine the frequency of Campylobacter spp, for which 45 samples were collected from 9 slaughter plants that supply chicken meat to the Ambato canton, the initial identification was carried out through microbiological and biochemical tests, such as the growth at 42°C, Gram stain, oxidase, catalase and motility, where 14 (31.11%) candidates for Campylobacter spp were obtained, however molecular identification by amplifying the 16S gene confirmed that the isolated bacteria were: Enterococcus faecalis, Enterococcus gallinarum, Aeromonas veronii, Escherichia coli, and Escherichia fergusonii. Finally, the risk factors associated with the contamination of chicken meat from the different slaughter plants were evaluated. In conclusion, it was possible to verify that the chicken meat from the slaughter plants under study contains potentially pathogenic bacteria for humans, putting consumers at great risk who develop gastrointestinal signs after consuming the contaminated meat.Item Determinación de Campylobacter spp. en muestras de carne de pollo que se expenden en el cantón Ambato(2023-03) Osorio Moreno, Lisbeth Mayte; Cruz Quintana, SandraChicken meat is a widely consumed food worldwide, while it is accessible to the majority of the population; Ecuador is a country that produces and consumes chicken meat. Being a food with an environment conducive to microbial growth, it tends to have pathogens that harm humans. Campylobacter spp. It is a gram negative bacterium that causes ETA and it is common to find it in chicken meat, its study being essential in the poultry industry and food safety. The purpose of this study was to determine Campylobacter spp. in chicken meat sold at authorized and informal points of sale in the Ambato canton, Tungurahua, Ecuador. Microbiological tests such as growth at 42 °C on Campylobacter selective agar, motility, Gram staining, and biochemical tests such as oxidase, catalase, and molecular identification were performed. Preliminarily, 6 (13.3%) and 5 (11.1%) positive samples were obtained from authorized and informal points, respectively. When performing molecular identification, no sample was positive for Campylobacter spp. Finally, the samples obtained contained microorganisms such as Enterococcus faecalis, Lactococcus garvieae, Enterococcus gallinarum, Pseudomonas aeruginosa, Escherichia coli and Aeromonas veronni. Risk factors related to chicken meat such as meat conservation, vendor protection measures, and premises hygiene indicate the predisposition of chicken meat to contamination, both in authorized premises and in informal premises.