Association of D516V, H526Y, and S531L rpoB Gene Polymorphisms and Rifampicin Resistant in Mycobacterium tuberculosis Isolates from Pulmonary TB Patients in Northwest Amhara, Ethiopia

Abstract

Tuberculosis (TB) is a pathogenic disease caused by Mycobacterium tuberculosis. Drug-resistant tuberculosis (DR-TB) continues to pose a threat to public health across the entire world. Rifampicin (RIF) resistance is mostly caused by mutations in the rpoB gene, which codes for the β -subunit of RNA polymerase and also an important surrogate marker for multidrug-resistant tuberculosis (MDR). The objective of this study was to detect the rpoB gene mutations associated with RIF resistance and identify the risk factor of MDR/RR drug resistance patterns in individuals infected with pulmonary TB. A facility based cross-sectional study was conducted at selected TB treatment center hospitals (Felegehiwot, Debre-tabor, University of Gondar, Debark, and Metema hospitals) from June to December 2023 in the Northwestern Amhara regional state of Ethiopia. A total of 206 culture-positive pulmonary TB patient samples were included. Socio-demographics, clinical and behavioral characteristics of the study participants were collected through semi structured questionary. Then All GeneXpert® MTB/RIF positive sputum specimens of bacterial isolates were cultured onto conventional egg-based solid Lowenstein-Jensen (LJ) medium. MTB Genomic DNA was extracted using GenoLyze Kit. Allele specific Amplification Refractory Mutation System Polymerase Chain Reaction (ARMS PCR) approach was employed on whole DNA samples from 206 Culture positive isolates using three distinct codon-specific primers (D516V, H526Y, and S531L). Most of the Single nucleotide polymorphism (SNP) mutations were observed on rpoB D531L 19 (9.2%). Of 206 confirmed clinical isolates, 21 (10.2%) were RIF Resistant, while the remaining 185 (89.8%) were RIF susceptible. Prior to TB treatment history (AOR = 4.27, CI 1.29-14.20, p= 0.02), TB/HIV-1 co-infection (AOR = 3.41, CI 1.12-10.33, p= 0.03) and Window opening practice of patients (AOR = 2.17, CI 1.22-31.29, p= 0.03) were significantly associated with RR-TB development. Hence, maximizing efforts for early detection of anti-TB drug resistance and controlling the occurrence of the disease are needed to reduce the public health impact of the disease in the study area. Keywords: ARMS-PCR, Mycobacterium tuberculosis, MDR/RR-TB, Rifam