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Introduction: A major sublineage within the Mycobacterium tuberculosis (MTB) LAM family characterized by a new in-frame fusion gene Rv3346c/55c was discovered in Rio de Janeiro (Brazil) in 2007, called RD Rio , associated to drug resistance. The few studies about prevalence of MTB RD Rio strains in Latin America reported values ranging from 3% in Chile to 69.8% in Venezuela, although no information is available for countries like Ecuador., Methods: A total of 814 MTB isolates from years 2012 to 2016 were screened by multiplex PCR for RD Rio identification, followed by 24-loci MIRU-VNTR and spoligotyping., Results: A total number of 17 MTB RD Rio strains were identified, representing an overall prevalence of 2.09% among MTB strains in Ecuador. While 10.9% of the MTB isolates included in the study were multidrug resistance (MDR), 29.4% (5/17) of the RD Rio strains were MDR., Discussion: This is the first report of the prevalence of MTB RD Rio in Ecuador, where a strong association with MDR was found, but also a very low prevalence compared to other countries in Latin America. It is important to improve molecular epidemiology tools as a part of MTB surveillance programs in Latin America to track the transmission of potentially dangerous MTB stains associated to MDR TB like MTB RD Rio ., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Castro-Rodriguez, Franco-Sotomayor, Benitez-Medina, Cardenas-Franco, Jiménez-Pizarro, Cardenas-Franco, Aguirre-Martinez, Orlando, Hermoso de Mendoza and Garcia-Bereguiain.)

Background: Tuberculosis (TB) is a major public health concern in Ecuador and Peru, both settings of high burden of drug resistance TB. Molecular epidemiology tools are important to understand the transmission dynamics of Mycobacterium tuberculosis Complex (MTBC) and to track active transmission clusters of regional importance. This study is the first to address the transmission of TB between Peru and Ecuador through the population structure of MTBC lineages circulating in the Ecuadorian border province of "El Oro"., Methods: A total number of 56 MTBC strains from this province for years 2012-2015 were included in the study and analyzed by 24-loci MIRU-VNTR and spoligotyping., Results: Genotyping revealed a high degree of diversity for MTBC in "El Oro", without active transmission clusters. MTBC L4 was predominant, with less than 2% of strains belonging to MTBC L2-Beijing., Conclusions: These results may suggest that TB dynamics in this rural and semi-urban area would not be linked to highly transmitted strains like MTBC L2-Beijing from Peru, but related to TB relapse; although further studies with larger MTBC cultures collection from recent years are needed. Nevertheless, we recommend to reinforce TB surveillance programs in remote rural settings and border regions in Ecuador., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Objective: Tuberculosis (TB) is a major public health concern in Ecuador and Colombia, considering that both countries are high-burden TB settings. Molecular epidemiology is crucial to understand the transmission dynamics of Mycobacterium tuberculosis complex (MTBC) and to identify active transmission clusters of regional importance., Methods: We studied the potential transmission of TB between Colombia and Ecuador through the analysis of the population structure of MTBC lineages circulating in the Ecuadorian province of Esmeraldas at the border with Colombia. A total of 105 MTBC strains were characterized by 24-loci MIRU-VNTR and spoligotyping., Results: MTBC lineage 4 is only present in Esmeraldas; no MTBC strains belonging to Lineage 2-sublineage Beijing were found despite its presence in other provinces of Ecuador and, in Colombia. Genotyping results revealed a high degree of diversity for MTBC in Esmeraldas: Neither active transmission clusters within this province nor including MTBC strains from Colombia or other provinces of Ecuador were found., Conclusion: Our data suggest that tuberculosis dynamics in this rural and isolated area may be not related to highly transmitted strains but could be influenced by other health determinants that favor TB relapse such as poverty and poor health system access. Further studies including a larger number of MTBC strains from Esmeraldas are necessary to test this hypothesis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Castro-Rodriguez, Espinoza-Andrade, Franco-Sotomayor, Benítez-Medina, Jiménez-Pizarro, Cárdenas-Franco, Granda, Jouvin, Orlando, Hermoso de Mendoza and García-Bereguiain.)