Molecular epidemiology of tuberculosis in Western Burkina Faso: insights from a MIRU-VNTR study

Tuberculosis (TB) remains a significant public health challenge in Burkina Faso, with limited molecular epidemiology data available to track strain diversity and transmission patterns. This study aims to characterize the genetic diversity of Mycobacterium tuberculosis complex (MTBC) isolates circulating in Burkina Faso via Mycobacterial Interspersed Repetitive-Unit Variable-Number Tandem-Repeat (MIRU-VNTR) typing.

Genotyping via the MIRU-VNTR technique, which is based on 24 loci, was performed via PCR amplification of DNA extracts from 80 MTBC isolates, followed by agarose gel electrophoresis. The genotypes obtained were identified via comparison with reference strains in the database via the MIRU VNTRplus web application. This study assessed strain diversity, clustering rates, and potential transmission patterns in the study area.

Among the 80 isolates, 94.5% were identified as M. tuberculosis sensu stricto, while 2.7% were M. africanum and 2.7% were M. bovis. The predominant lineages were Cameroon (26.3%), Ghana (26.3%), and Haarlem (20%), with the Beijing lineage being rare (1.25%). A low clustering rate of 2.5% was observed. The average discriminating power (allelic diversity index) was 0.444. Eight loci were highly discriminative (h ≥ 0. 6) versus 3 loci that were weakly discriminating (h < 0.3).

This study provides new insights into the genetic diversity and transmission dynamics of MTBC strains in Burkina Faso. While the observed low clustering suggests limited recent TB transmission, the findings require further validation through larger-scale studies incorporating whole-genome sequencing (WGS). Understanding TB strain diversity is crucial for optimizing diagnostic strategies and TB control policies in West Africa.