Molecular characterization of mycobacterial strains from clinical specimens of patients with tuberculosis

Tuberculosis (TB) is the leading cause of death amongst the curable infectious diseases which is a major public problem globally. Furthermore, the increasing emergence of multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) presents a major threat to effective control of TB (Zhang and Yew, 2009). In 2010, TB incident cases were estimated to be 9.4 million globally, with approximately 1.8 million deaths. India and China accounted for 40% of the world’s notified cases of TB in 2010; Africa accounted for a further 24%, of which one quarter was in South Africa (SA). SA is the world’s third highest burden TB country, ranked the fifth highest drug resistant (DR-TB) high burden country, only lagging behind countries with significantly larger populations, China and India (SA MDR-TB guidelines, 2011). In addition, the numbers of MDR-TB and XDR-TB patients have increased due to the concurrent human immunodeficiency virus (HIV) infection HIV epidemic and inadequate management of TB (WHO, 2011). It is estimated that more than 500,000 TB cases are diagnosed each year in SA. Since the first detection of MDR-TB in 1985, an estimated 15000 new MDR- TB cases are reported each year. In 1997, the first XDR-TB case was detected and, more than 600 new cases are diagnosed each year since 2007. Research shows that in SA, MDR-TB/XDR-TB is predominantly driven by transmission of resistant strain that infects healthy individuals, due to slow diagnostic methods, which allow undiagnosed drug resistant cases to spread the disease while inappropriate and weak treatment regimens leads to the amplification of drug resistance in the communities, and poor management of DR-TB cases (www.moleculartb.org/gb/pdf/transcriptions/13_Victor_2109.pdf) The communities surrounding DGMH are highly TB burdened, and approximately 70% of these patients, are co-infected with HIV. Irrespective of increased rapid diagnostic methods in the detection of Mycobacteria and DR-TB, currently, there is no data that specifies drug resistant strains and their mechanisms of resistance, prevalence of mixed infections, prevalence of circulating species of non-tuberculous mycobacteria (NTMs) as well as their clinical outcomes.