Introducción. Los aislados de Mycobacterium tuberculosis pertenecientes al linaje Beijing son considerados especialmente virulentos, transmisibles y con mayor tendencia a la adquisición de resistencias. El linaje Beijing ha sido descrito en todo el mundo, sin embargo estudios al respecto son más escasos en Latinoamérica. El único estudio multinacional realizado en la region detectó una distribución heterogénea de este linaje, estando ausente en Chile, Colombia y Ecuador. Estudios nacionales posteriores ya identificaron aislados Beijing en Chile y Colombia.Objetivo. Analizar la presencia del linaje Beijing de M. tuberculosis en Ecuador, el único país en la región en el que aún permanece inédito.Materiales y métodos. Se analizó una muestra de conveniencia (2006-2012), obtenida de dos hospitales que cubrían poblaciones diferentes. El genotipado de los aislados de M. tuberculosis se realizó por 24-MIRU-VNTR. La asignación de linajes se realizó mediante comparación de los patrones genotípicos con los incluidos en la plataforma MIRU-VNTRplus y aquellos pertenecientes al linaje Beijing fueron confirmados mediante PCR alelo-específica.Resultados. Se identificó el primer aislado Beijing descrito en Ecuador, en un escenario epidemiológico inesperado, infectando a un paciente de la región andina, en una comunidad con escasa movilidad y alejada de las fronteras con los países limítrofes, Perú y Colombia, en los que ya se han identificado aislados de M. tuberculosis pertenecientes al linaje Beijing.Conclusiones. Este trabajo constituye la primera descripción de la presencia del linaje Beijing de M. tuberculosis en Ecuador, y sugiere un contexto epidemiológico singular que merece especial atención.
Species within the Mycobacterium tuberculosis (MTB) Complex are genetically monomorphic, hence the need of genotyping methods for a comprehensive understanding of the epidemiology of the disease. The genetic diversity of a Spain collection of eighty-three, GenoType MTBC® -confirmed Mycobacterium tuberculosis clinical isolates was assessed by simplified AFLP and 15-loci MIRU-VNTR. AFLP results showed 7 patterns (P1-P7), Dice´s coefficient was 71% for P1 vs P7 and 96% for P1 vs P2 and P2 vs P4. MIRU-VNTR showed 25 unique patterns and 14 clusters. Lineages found were as follows: Haarlem (23, 36.51%), Cammeroon (2, 3.17%), LAM (12, 19.05%), West African (6, 9.52%) and EAI (1, 1.59%). Discrimination indexes were 0.61 for AFLP and 0.92 for MIRU-VNTR. In conclusion, MIRU-VNTR is robust and reproducible for MTB genotyping. Simplified AFLP is a relatively easy-to-perform approach that might be useful for screening of isolates or in low resource settings.
Introduction: There are limited longitudinal data on the systemic and mucosal antibody responses to SARS-CoV-2 from Latin America, a region severely affected by COVID-19, and where vaccine strategies have been implemented during the evolving pandemic. Objective: To evaluate determinants of seroprevalence and changes in levels of anti-SARS-CoV-2 antibodies longitudinally in adults with different levels of exposure to SARS-CoV-2 (defined a priori as low, medium, and high based on presumed occupational risk), in two Andean cities in Ecuador. Methods: Longitudinal cohort study of 1,000 adults aged 18 years and older with questionnaire data and sample collection done at 0, 3, 6, and 12 months during the period 2020-2023. Observations collected included WHO-ISARIC questionnaire and peripheral blood and saliva samples for measurement of IgG and IgA antibodies, respectively. Planned analyses are tailored to the longitudinal nature of the outcomes defined by participants’ antibody levels and aim at estimating their average trends with time since infection in each of the occupational groups, adjusted for demographics and calendar-time levels of SARS-CoV-2 infection in the general population. The latter reflect the impact of the national control measures such as vaccinations and movement restrictions. Importance: Understanding the duration and the dynamics of waning immunity to SARS-CoV-2, in the context of exposures to emerging virus variants and immunization, will inform the implementation of targeted public health strategies in the Latin American region. Ethics and Dissemination: This study will observe the bioethical principles of the Declaration of Helsinki. Informed written consent will be obtained. Samples from participants will be stored for up to three years after which they will be destroyed. The study protocol was approved by the Ecuadorian Ministry of Public Health Ethics Committee for COVID-19 Research. Antibody results will be provided to participants and participating institutions and to the national health authorities.
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