Characterization of clinical isolates of Mycobacterium tuberculosis from indigenous peoples of Colombia

Introduction: Tuberculosis continues to be a public health priority. Indigenous peoples are vulnerable groups with cultural determinants that increase the risk of the disease.
Objective: To determine molecular epidemiology and phenotypical features and of Mycobacterium tuberculosis isolates from indigenous people in Colombia during the period from 2009 to 2014.
Materials and Methods: We conducted an analytical observational study; we analyzed 234 isolates to determine their patterns of sensitivity to antituberculosis drugs and their molecular structures by spoligotyping.
Results: The isolates came from 41 indigenous groups, predominantly the Wayúu (13.10%) and Emberá Chamí (11.35%). We found 102 spoligotypes distributed among seven genetic families (37.2% LAM, 15.8% Haarlem, 8.1% T, 3.4% U, 2.6% S, 2.1% X, and 0.9%, Beijing). The association analysis showed that the non-clustered isolates were related to prior treatment, relapse, orphan spoligotypes, and the Beijing family. The H family presented an association with the Arhuaco and Camëntŝá indigenous groups, the U family was associated with the Wounaan group, and the T family was associated with the Motilón Barí group.
Conclusions: This is the first national study on M. tuberculosis characterization in indigenous groups. The study evidenced that diagnosis in indigenous people is late. We described 53% of orphan patterns that could be typical of the Colombian indigenous population. The high percentage of grouping by spoligotyping (62%) could indicate cases of active transmission, a situation that should be corroborated using a second genotyping marker. A new Beijing spoligotype (Beijing-like SIT 406) was identified in Colombia.