LAUSR

The Beijing family, the most successful Mycobacterium tuberculosis lineage, is considered hypervirulent, associated with clustering and has a strong association with multidrug-resistant tuberculosis. The Beijing strains have spread worldwide and also to Latin America. Genotyping of a countrywide collection of 380 M. tuberculosis strains from Ecuador, with 24-loci mycobacterial interspersed repetitive units-variable number tandem repeats (MIRU-VNTR), revealed only six Beijing strains, but four of these were MDR-TB. There was no clustering as all six strains had very distinct MIRU-VNTR profiles that have not been reported in the rest of Latin America. Although active transmission for Beijing has been described for the neighboring countries Peru and Colombia, there is no evidence that Beijing strains in Ecuador are more frequently transmitted than other strains. Moreover, the low prevalence (1.6%) of the Beijing sublineage in Ecuador challenges the concept of hyperadaptability and transmissibility of the Beijing strains in our country.