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1.
Colomb. med ; 43(1): 38-45, Jan.-Mar. 2012. tab, graf
Article Dans Anglais | LILACS | ID: lil-673542

Résumé

Introduction: Listeria monocytogenes is a pathogen acquired through the consumption of contaminated foods.Thirteen serotypes have been reported, of which 1/2a, 1/2b, and 4b are responsible for 98% of human listeriosis cases. This study examines the association between serotypes and virulent clones, offering greater information and providingtools to prevent and control diseases caused by L. monocytogenes serotype 4b. Objective: To identify the serotypes from L. monocytogene strains isolated from different samples by performingthe molecular subtyping technique; to determine the 85M fragment that codifies for epidemic clone I.Methods : 108 strains of L. monocytogenes were used, isolated from samples of animals, body fluids, foods, and food processing plant equipment and spaces. The samples were identified by following the Bacteriological AnalyticalManual protocol described by the Food and Drug Administration (FDA). The strains were identified by PolymeraseChain Reaction (PCR) using primers and a standardized protocol from a previous research project. Serotypeidentification was performed by multiplex PCR. The determination of the 85M fragment of the SSCS cassette was done by following the protocol by Yildrim et al. Results : Of the 108 L. monocytogenes strains analyzed, 60.2% (65 strains) belonged to the 4b-4d-4e serotype, 17.6%(19 strains) were identified as 1/2a-3a serotype, 14.8% (16 strains) were 4a-4c serotype, 3.7% (4 strains) belonged to the 1/2c-3c serotype, and (3.7%) corresponded to the 1/2b-3b-7 serotype. It was determined that the L. monocytogenes strains serotype 4b-4d-4e and 1/2a-3b have the 85M fragment of the SSCS cassette.Conclusion : This study reports the predominant existence of L. monocytogenes strains serotype 4b-4d-4e in food, environmental, and clinical samples. The presence of an epidemic clone I region was also found in L. monocytogenes strains.


Sujets)
Séparation cellulaire , Infections à Listeria
2.
Biomédica (Bogotá) ; 26(3): 442-450, sept. 2006. ilus
Article Dans Espagnol | LILACS | ID: lil-475410

Résumé

Introducción. Listeria monocytogenes es un patógeno emergente adquirido por el consumo de alimentos contaminados. Causa una enfermedad llamada listeriosis, cuya tasa de mortalidad a nivel mundial varía entre 20 por ciento y 30 por ciento, alcanzando hasta un 80 por ciento en casos de infecciones neonatales. La técnica del ADN polimorfo amplificado aleatorio permite distinguir entre diferentes aislamientos y caracterizarlos molecularmente, lo cual aporta información útil acerca de la diversidad de este patógeno en Colombia. Objetivo. Caracterizar molecularmente diferentes aislamientos de L. monocytogenes aisladas de muestras clínicas y alimentos utilizando ésta técnica para determinar posibles relaciones entre estos dos orígenes. Materiales y métodos. Se analizaron 38 aislamientos de L. monocytogenes; 22 de muestras clínicas y 16 de alimentos y plantas procesadoras de alimentos utilizando dos oligonucléotidos de 10pb (HLWL-74 y Arbitrario). Los datos se analizaron utilizando los programas Quantity One y SYN-TAX. Resultados. Se detectó un alto porcentaje de polimorfismo mediante los oligonucleótidos HLWL-74 (81,81 por ciento) y Arbitrario (85,71 por ciento). Se pudieron describir dos linajes superiores luego del análisis, los cuales se dividieron a su vez en cuatro grupos mayores (A, B C y D) donde se observó una gran diversidad genética. La mayoría de aislamientos clínicos se agruparon bajo el mismo grupo y se encontraron alejados de los aislamientos de alimentos. Conclusión. Los resultados de este estudio demuestran que existe una gran diversidad de polimorfismos de ADN entre los aislamientos de L. monocytogenes que circulan en Colombia, lo que podría reflejar diferencias a nivel fenotípico y patogénico en estos aislamientos.


Introduction. Listeria monocytogenes is an emergent foodborne pathogen acquired by the ingestion of contaminated food. This bacterium causes a disease called listeriosis, whose mortality rate world wide is around 20% to 30%, reaching up to 80% in cases of neonatal infections. The random amplified polymorphic DNA technique allows different isolates to be distinguished and characterized at the molecular level, which can provide useful information about the diversity of this pathogen in Colombia. Objective. To molecularly characterize different L. monocytogenes isolates from food and clinical samples using this technique to determine possible relationships among these two origins. Materials and methods. Thirty eight L. monocytogenes isolates were analyzed; 22 from human clinical samples and 16 from food processing plants and food using two 10bp primers (HLW74, Arbitrary). The data were analyzed using Quantity One and SYN-TAX software. Results. A high percentage of polymorphism was detected with both primers (HLWL-74, 81,81%; Arbitrary, 85,71%). Two major lineages were found, which were divided into four major clusters (A, B C y D) and great genetic diversity was observed. Most of the clinical isolates were grouped within the same cluster, and were more distantly related to the food isolates. Conclusion. The results of this study demonstrate a high degree of genetic diversity of DNA polymorphisms among the L. monocytogenes isolates circulating in Colombia, which could reflect phenotypic and pathogenic differences in these isolates.


Sujets)
Échantillons Alimentaires , Listeria monocytogenes , Conformation moléculaire
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