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EPIDEMIOLOGÍA MOLECULAR DE MYCOBACTERIUM TUBERCULOSIS EN EL ESTADO AMAZONAS (VENEZUELA)

ABSTRACT Resumen. Venezuela posee una tasa de incidencia de tuberculosis (TB) moderada con respecto a los países latinoamericanos, el Estado Amazonas es uno de los estados con mayor Incidencia de TB en nuestro país. Para conocer mejor la epidemiología molecular de la TB en Amazonas, se aislaron 100 cepas de Mycobacterium tuberculosis durante el periodo enero 1998-junio 2004. Estas cepas fueron analizadas con la herramienta de epidemiología molecular del Espoligotipaje (Spoligotyping), los resultados de esta técnica fueron relacionados con la localidad geográfica y la etnia del cada paciente. Además, los espoligotipos obtenidos fueron comparados con la base de datos nacional SpolDB.Vz2 y la base de datos mundial SpolDB4 (1). Los genotipos hallados, son consistentes con los de otros estados de Venezuela, donde las familias de espoligotipos mas prevalentes son las (Latino Americana-Mediterránea) (LAM), Haarlem y T1. Además, hubo spoligotipos no reportados previamente en el país y tres nuevos grupos: AMA-G1, AMA-G2 y AMA-G3. Se encontró asociaciones entre algunos spoligotipos, etnias y localidades específicas. Estos hallazgos dan una sólida referencia para el monitoreo de cambios en la composición de las cepas circulantes en la población amazonense como consecuencia de la introducción de nuevas cepas de otros estados o países vecinos. Palabras claves: tuberculosis, Espoligotipaje, Amazonas. MOLECULAR EPIDEMIOLOGY OF MYCOBACTERIUM TUBERCULOSIS IN THE AMAZONAS STATE (VENEZUELA) Summary. Venezuela has a moderate incidence of Tuberculosis (TB), while the Amazons State is one with the highest incidence in the country. To obtain a better knowledge of the regional TB epidemiology, 100 isolates of Mycobacterium tuberculosis

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    ABSTRACT: Tuberculosis remains an endemic public health problem, but the ecology of the TB strains prevalent, and their transmission, can vary by country and by region. We sought to investigate the prevalence of Mycobacterium tuberculosis strains in different regions of Venezuela. A previous study identified the most prevalent strains in Venezuela but did not show geographical distribution nor identify clonal genotypes. To better understand local strain ecology, we used spoligotyping to analyze 1298 M. tuberculosis strains isolated in Venezuela from 1997 to 2006, predominantly from two large urban centers and two geographically distinct indigenous areas, and then studied a subgroup with MIRU-VNTR 24 loci. The distribution of spoligotype families is similar to that previously reported for Venezuela and other South American countries: LAM 53%, T 10%, Haarlem 5%, S 1.9%, X 1.2%, Beijing 0.4%, and EAI 0.2%. The six most common shared types (SIT's 17, 93, 605, 42, 53, 20) accounted for 49% of the isolates and were the most common in almost all regions, but only a minority were clustered by MIRU-VNTR 24. One exception was the third most frequent overall, SIT 605, which is the most common spoligotype in the state of Carabobo but infrequent in other regions. MIRU-VNTR homogeneity suggests it is a clonal group of strains and was named the "Carabobo" genotype. Epidemiologic comparisons showed that patients with SIT 17 were younger and more likely to have had specimens positive for Acid Fast Bacilli on microscopy, and patients with SIT 53 were older and more commonly smear negative. Female TB patients tended to be younger than male patients. Patients from the high incidence, indigenous population in Delta Amacuro state were younger and had a nearly equal male:female distribution. Six SIT's cause nearly half of the cases of tuberculosis in Venezuela and dominate in nearly all regions. Strains with SIT 17, the most common pattern overall may be more actively transmitted and SIT 53 strains may be less virulent and associated with reactivation of past infections in older patients. In contrast to other common spoligotypes, strains with SIT 605 form a clonal group centered in the state of Carabobo.
    BMC Infectious Diseases 09/2009; 9:122. · 3.03 Impact Factor

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