ABSTRACT
A recent report by the World Health Organization pointed out that about 3.3% of the new cases of tuberculosis were caused by multi-drug resistant strains that do not respond to drugs like rifampicin (RIF) or isoniazid (INH), which are first-line drugs for treatment of tuberculosis. Different countries have reported that over 18% of fresh cases and over 50% of cases previously treated have been identified to be associated with multi-drug resistant Mycobacterium tuberculosis. This study aimed to identify specific resistance to all first line drugs by detecting particular resistant genes and analyzing drug sensitivity with the purpose of providing genetic mapping of the presence of these genes or amino acids in a sample population of Mycobacterium tuberculosis patients in Bayelsa State.
The ethical approval for the study was obtained from the Bayelsa State Ministry of Health (BYSMOH) as well as Federal Medical Center, Yenagoa. The procedure of the study was adopted from the handbook on tuberculosis laboratory diagnostic methods. Following clinical diagnosis, 110 patients were screened using the Ziehl-Neelsen method and Gene-Xpert to confirm positive Mycobacterium tuberculosis and resistance as well as susceptibility status. DNA extraction was carried out followed by Polymerase Chain Reaction amplification method. Molecular studies were carried out using standard procedures.
The findings in this study revealed that Mycobacterium tuberculosis infections were more common among young males than in females. Based on occupation, Mycobacterium tuberculosis infection was highest among the traders followed by the farmers. GeneXpert and DNA sequencing revealed that rifampicin resistant tuberculosis was most common among traders in Bayelsa State. Genexpert and DNA sequence also revealed that there was no remarkable isoniazid, rifampicin and ethambutol co-resistance tuberculosis infection which suggest that prevalence of Multi-drug Resistant tuberculosis in Bayelsa State is low. The findings showed more Mycobacterium tuberculosis positive patients among the males within 25-46 age range, with occupational data revealing that, of the 14 students, 2 (12.5%) harbored the rifampicin resistance, 4 (25.0%) of the 19 farmers, 6 (37.5%) out of 53 traders showed the rifampicin resistance respectively. Using the DNA sequencing of rpoB, katG, and embB in analysing resistance of rifampicin, isoniazid, and ethambutol showed single nucleotide polymorphism (SNP). The study revealed that 15 patients showed SNP for rpoB, 14 showed SNP for katG, 11 showed SNP for embB while no patient showed SNP for inhA. Fifteen of the male and female of all the ages investigated for gene mutations showed more rpoB gene mutations amongst the males; more katG gene mutation among the female patients; equal mutation of embB gene among the traders and civil servants. The lack of Multidrug resistance tuberculosis based on the results of this study suggests the effectiveness of the first line anti-TB drugs, amongst TB patients in Bayelsa state.
