BackgroundTuberculosis 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.ResultsThe 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.ConclusionSix 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.

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Objetivos: Tipificar el casette SCCmec en cepas de Staphylococcus aureus resistentes a meticilino (SARM) en aislados clínicos de centros de salud del Estado Aragua-Venezuela y comparar la presencia de los genotipos SCCmec entre los centros de salud del estado y según el tipo de infección. Materiales y métodos: Durante enero y agosto de 2015 se estudiaron 81 cepas SARM de cuatro centros de salud del estado de Aragua en Venezuela. La resistencia al meticilino se midió con el método de Kirby-Bauer con discos de oxacilina (1 μgr) y cefoxitina (30 μgr). El gen mecA y el SCCmec se analizaron por la técnica de reacción en cadena de polimerasa múltiple. Resultados: 55 aislados (67,9%) amplificaron el gen mecA, y 24 cepas (43,6%) amplificaron el SCCmec. El SCCmec I fue el más frecuente, seguido de SCCmec IV y SCCmec III, representaron el 62,5%, 25% y 12,5%, respectivamente. El SCCmec I fue predominante en el centro de salud A (80%), mientras que el SCCmec IV se encontró en el centro de salud B (60%) y C (100%). En el centro de salud D, 50% resultó ser SCCmec I y 50% SCCmec IVd. Se encontró relación entre el SCCmec y el centro de salud con significancia estadística. En infecciones de piel y tejidos blandos y en las respiratorias predominó el SCCmec I con 63,2% y 50% respectivamente. Conclusiones: La frecuencia de SCCmec I y IV permitirá establecer nuevas medidas en el uso y control de la resistencia a los antibióticos.