Assessment of extremely drug resistant tuberculosis (XDR-TB) prevalence among multi drug resistant tuberculosis (MDR-TB) cases in Zambia using Geno type MTBDR Assa

Tuberculosis (TB) remains a global public health problem that claims millions of lives every year. The emergence of drug resistant tuberculosis has been recognised as the major threat to the control of TB. The first most important drug resistant TB is the Multi-drug resistant tuberculosis (MDR-TB).
We carried out a retrospective study of 113 MDR-TB isolates stored from 2008 to 2015 to determine the presence of Extremely Drug Resistant Tuberculosis (XDR-TB). These isolates were retrieved from the three TB culture laboratories of Zambia ((Tropical Diseases Research Centre (TDRC), University Teaching Hospital (UTH) and the Chest Diseases Laboratories (CDL)).
A total of 113 MDR-TB isolates were subjected to GenoType MTBDRsl assay to detect any mutations associated with resistance to fluoroquinolones, aminoglycosides-capreomycin and ethambutol.
Out of the 113 MDR-TB Isolates, one isolate had mutation at gyrA and rrs MUT1 with absence of rrs WT1. The isolate belonged to a 22 year old female MDR-TB patient who was attended to at a local clinic with resistance to Streptomycin, Isoniazid, Ethambutol and Rifampicin. One other isolate showed mutation in the gyrA region only. This was an MDR-TB male patient aged 38 years who was also earlier diagnosed with resistance to Streptomycin, Isoniazid, Ethambutol and Rifampicin. No mutations were observed in about 111 (98.2%) isolates.