Drug resistant tuberculosis cases from the Copperbelt province and Northern regions of Zambia: Genetic diversity, demographic and clinical characteristics

Abstract

Tuberculosis (TB) caused by Mycobacterium tuberculosis remains a major cause of death worldwide. Diverse genotypes have been demonstrated to drive the epidemiology of drug resistant (DR-) TB globally. Currently, there is limited knowledge on the genotypes and transmission dynamics of M. tuberculosis in Zambia. This study aimed to describe the genotypes of DR-TB from the Copperbelt and Northern regions of Zambia. Molecular typing tools of insertion sequence 6110-restriction fragment length polymorphism (IS6110-RFLP) and spacer oligonucleotide typing (spoligotyping) were applied. We demonstrate that diverse genotypes are associated with DR-TB in Zambia. The predominant genotype was lineage 4; other strains belonged to lineage 2 and 3. Genotypes previously identified as driving the epidemiology of drug susceptible TB have been identified as drivers of DR-TB. Genotyping analysis showed clustering of strains among patients from different regions of the country; suggesting that DR-TB is widespread. Molecular findings combined with phenotypic and epidemiologic findings play a critical role in identifying circulating genotypes and possible transmission chains. Clustering of drug resistant strains was demonstrated to be 48% and 86% according to IS6110-RFLP and spoligotyping, respectively. However, gaps in clinical and demographic data skew the interpretation, and call for data collection policy improvements.

Keywords: Drug resistant; IS6110-RFLP; Mycobacterium tuberculosis; Spoligotyping; Zambia.