[Identification of the Mycobacterium tuberculosis Beijing lineage in Ecuador]

Abstract

Introduction: Mycobacterium tuberculosis Beijing lineage isolates are considered to be especially virulent, transmissible and prone to acquire resistances. Beijing strains have been reported worldwide, but studies in Latin America are still scarce. The only multinational study performed in the region indicated a heterogeneous distribution for this lineage, which was absent in Chile, Colombia and Ecuador, although further studies found the lineage in Chile and Colombia.

Objective: To search for the presence of the Beijing lineage in Ecuador, the only country in the region where it remains unreported.

Materials and methods: We obtained a convenience sample (2006-2012) from two hospitals covering different populations. The isolates were genotyped using 24-MIRU-VNTR. Lineages were assigned by comparing their patterns to those in the MIRU-VNTRplus platform. Isolates belonging to the Beijing lineage were confirmed by allele-specific PCR.

Results: We identified the first Beijing isolate in Ecuador in an unexpected epidemiological scenario: A patient was infected in the Andean region, in a population with low mobility and far from the borders of the neighboring countries where Beijing strains had been previously reported.

Conclusion: This is the first report of the presence of the Beijing lineage in Ecuador in an unusual epidemiological context that deserves special attention.

Keywords: Ecuador; Mycobacterium tuberculosis; case reports; molecular epidemiology; tuberculosis; virulence.