Tracking characterization of Mycobacterium strains in Tanzania and some sub-Saharan African countries: an overview on genotyping studies, implication and trends in advancing technology

Abstract

Tuberculosis (TB) is a devastating chronic debilitating infection that imposes a considerable negative impact on human health. The disease also affects the quality of livestock, wildlife and their products. Mycobacterium tuberculosis (M. tuberculosis) is the causative agent for human TB, while Mycobacterium bovis (M. bovis) predominantly causes TB in animals, though is also zoonotic. In Tanzania and other developing countries timely diagnosis of disease is hampered by poor access to appropriate capacity and technology to characterize the pathogen. This review explores the diverse methods available for the diagnosis and characterization of Mycobacterial species and strains isolated from both humans and animals in sub Saharan Africa. The review will identify knowledge gaps and highlight direction for future investigation of the interface TB risk, which could lead to a better regional control strategy. A systematic search of PubMed, Google and Google Scholar retrieved 716 published articles on TB and methods used with the aim of tracking the advancement in technology and to reflect where we are and what can best be done to improve the strategy for best control of the disease. The search terms included but not limited to “(Whole Genome Sequencing AND sub-Saharan Africa); (Diverse TB strains + Human +Animals) AND Tanzania + Africa + Sub-Saharan Africa; (Diverse TB strains + human+ animals) OR Tanzania + Africa + Sub-Saharan Africa)”. The review illustrates an advancement of technology from 1950s to 2000s with only 17.7% studies having been done using DNA-based methods and 81.3% being studies that used conventional methods. Most of the molecular studies cluster in the mid- to late 2000s which could be due to lack of expertise, slow adoption of technology or the high cost of running these valuable molecular tests. This overview on genotyping studies and trend in molecular studies highlights the need for more investment in this region of the world. An increased use of molecular methods will help in increasing the chances of detecting new TB strains in circulation and identifying potential risks for cross-transmission at humans-livestock-wildlife interface. A strengthened ability to detect and characterizes disease will better support country and regional control strategies.