Detección de genes de resistencia a antibióticos en carnes de pollo comercializadas en Valencia

Abstract

[ES] La OMS (Organización Mundial de la Salud) ha declarado que las resistencias bacterianas a antibióticos suponen uno de los mayores problemas para la salud y seguridad alimentaria. A pesar de ser un fenómeno que ocurre naturalmente, el reciente abuso por parte de la industria ganadera y el ser humano han acelerado el proceso significativamente. Asimismo, la facilidad bacteriana para adquirir genes de resistencia mediante transferencia horizontal por vía de plásmidos supone una preocupación adicional a la generación de bacterias resistentes, en especial en aquellas patógenas o con multirresistencias, por el potencial riesgo que supone para el consumidor. Teniendo esto en cuenta, este trabajo de fin de grado propone detectar la presencia en genes de resistencia en carnes avícolas de consumo humano y en bacterias aisladas de las mismas comercializadas en la Comunidad Valenciana. Para ello, se realizará un aislamiento de cepas de interés utilizando medios selectivos, y después se detectará la presencia de genes de resistencias a antibióticos del grupo de beta-lactámicos (blaTEM, blaCMY, blaSHV), carbapenémicos (blaKPC, blaVIM, blaIMP, blaOXA) y quinolonas por medio de PCR.

[EN] The World Health Organization has declared that antibiotic-resistant bacteria represent one of the most significant issues for health and food safety. Although it is a naturally occurring phenomenon, the recent abuse by the livestock industry and humans has created a selective pressure that has significantly accelerated the process. Additionally, bacteria's ability to couple resistance genes through horizontal transfer via plasmids poses an additional concern regarding the generation of resistant bacteria, especially those that are pathogenic or have multiple resistances. In this undergraduate thesis, 20 samples of chicken meat sold in the city of Valencia were analyzed to determine the role of the bacteria present as reservoirs of antibiotic resistance genes and as vectors of transmission to humans. To achieve this, coliform isolation and counting were performed to obtain indicator strains of E. coli. Simultaneously, selective isolation was conducted to detect the presence or absence of the Salmonella genus and Listeria monocytogenes. A final directed isolation was carried out using selective culture media to obtain bacteria resistant to carbapenem and third- generation cephalosporin antibiotics. All isolated bacteria were filtered through initial biochemical tests to retain only those of interest: oxidase-negative, catalase-positive, and gram-negative. Subsequently, biochemical identification was performed using API strips and a second identification by sequencing the 16s rRNA gene. Finally, the presence of resistance genes to β-lactam antibiotics (blaTEM, blaCMY, blaSHV), carbapenems (blaKPC, blaVIM, blaOXA, blaIMP), and quinolones (qnrA, qnrB, qnrS) was detected. Among the isolated strains, 67.53% had at least one resistance gene, 44.23% had more than one class of resistance genes, and one strain had all three classes analyzed. This project is primarily related to the following sustainable development goals: SDG 1 End Poverty; SDG 2 Zero Hunger; SDG 3 Health and Well-being; SDG 8 Decent Work and Growth; and SDG 12 Responsible Consumption and Production.