Publication: Diversidad genética y persistencia ambiental de "Listeria Monocytogenes" en dos plantas de procesado de carne de cerdo ibérico: influencia de la resistencia a desinfectantes de amonio cuaternario
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2016-07-01
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Universidad Complutense de Madrid
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Abstract
La clasificación en subtipos moleculares de los aislados de L. monocytogenes procedentes de productos cárnicos y del ambiente de las plantas de procesado donde se elaboran, habitualmente muestra la presencia de un reducido número de cepas y la persistencia durante largos periodos de tiempo de cepas específicas que sobreviven a la limpieza y la desinfección. Entre los mecanismos que facilitan la supervivencia de L. monocytogenes en el ambiente de las plantas de procesado de alimentos se incluyen la formación de biofilm, la adquisición de resistencia a antimicrobianos y la resistencia al estrés. El objetivo inicial de esta tesis fue analizar los diferentes subtipos de L. monocytogenes que se encontraban contaminando el ambiente y los productos de una planta de sacrificio y elaboración de productos de cerdo ibérico (Planta A) durante un periodo de tres años, con el fin de identificar las rutas de contaminación y posibles patrones de persistencia. Mediante electroforesis en gel en campo pulsante (PFGE) se identificaron 29 pulsotipos diferentes, ocho de los cuales se consideraron persistentes. La distribución en el ambiente y en los productos de tres pulsotipos predominantes generó patrones de contaminación específicos de cada uno de ellos, que mostraron respuestas diferentes ante las medidas correctoras que se adoptaron en la planta. Estos resultados destacan la importancia de la caracterización molecular de los subtipos de L. monocytogenes para identificar las rutas de contaminación específicas de la planta, que permitieron mejorar las estrategias de control de la contaminación...
Different reports on molecular typing of L. monocytogenes from the environment and products of meat-processing plants indicate the presence of a limited number of strains or genotypes, together with the persistence of specific strains even after cleaning and disinfection procedures. Mechanisms that facilitate the survival of L. monocytogenes in food processing environments include biofilm formation, acquisition of antimicrobial resistance, and stress resistance. The initial aim of this thesis was to track the different subtypes of L. monocytogenes that were contaminating the environment and products from an Iberian pig slaughterhouse and processing plant (Plant A) during a three-year period, to identify contamination routes and possible persistence patterns. Pulsed-field gel electrophoresis (PFGE) restriction analysis allowed the identification of 29 different PFGE types, eight of them were considered persistent. Distribution of three dominant PFGE types in the environment and products generated specific contamination patterns of each PFGE type, which showed different response to corrective measures taken in the plant. The result highlighted that molecular subtyping methods can help identify plant-specific contamination routes for the implementation of improved control strategies..
Different reports on molecular typing of L. monocytogenes from the environment and products of meat-processing plants indicate the presence of a limited number of strains or genotypes, together with the persistence of specific strains even after cleaning and disinfection procedures. Mechanisms that facilitate the survival of L. monocytogenes in food processing environments include biofilm formation, acquisition of antimicrobial resistance, and stress resistance. The initial aim of this thesis was to track the different subtypes of L. monocytogenes that were contaminating the environment and products from an Iberian pig slaughterhouse and processing plant (Plant A) during a three-year period, to identify contamination routes and possible persistence patterns. Pulsed-field gel electrophoresis (PFGE) restriction analysis allowed the identification of 29 different PFGE types, eight of them were considered persistent. Distribution of three dominant PFGE types in the environment and products generated specific contamination patterns of each PFGE type, which showed different response to corrective measures taken in the plant. The result highlighted that molecular subtyping methods can help identify plant-specific contamination routes for the implementation of improved control strategies..
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Tesis inédita de la Universidad Complutense de Madrid, Facultad de Veterinaria, Departamento de Nutrición, Bromatología y Tecnología de los Alimentos, leída el 30/11/2015