Presencia del genotipo Beijing entre cepas del complejo Mycobacterium tuberculosis en dos centros de salud de la Región Metropolitana-Chile

Background: Genotyping of Mycobacterium tuberculosis complex (cMtb) allows us to know geographically predominant lineages. Some lineages spread more rapidly and are associated with multidrug resistance, particularly Beijing, which has been reported in Latin America (Peru). There is little information about this topic in Chile and there are no reports of the presence of the Beijing genotype. Aim: To determine the most prevalent lineages in the Metropolitan Region of Chile with emphasis on the search for Beijing in two health centers. Methods: Two complementary molecular methods were used: spoligotyping, based on the variations of the direct repeat regions in the genome of cMtb and MIRU-VNTR, based in the variable number of tandem repeats of mycobacterial interspersed repetitive units, and subsequent analysis in international databases. A designed lineage was assigned to 37 of the 43 strains studied (86%); 6 isolates could not be assigned to any genotype. LAM and T genotype were the most frequent (39.5 and 32.5%, respectively) followed by Haarlem (7.0%), Beijing (4.7%) and X (2.3%). Conclusion: We describe for the first time the presence of the Beijing genotype in Chile. cMtb molecular surveillance should be implemented in our country in order to know the dynamics of its transmission.