Identification of potential mutations associated with multidrug resistance among isolates of Mycobacterium tuberculosis in Malaysia by in silico screening

Abstract

The emergence of multidrug resistance tuberculosis (MDR-TB) is caused by Mycobacterium tuberculosis (MTB) adaptation to survive in the presence of antibiotic, that were contributed by mutations in the MDR-associated genes. Previous research has indicated that the gene expression knockdown of fhaA leads to an accumulation of peptidoglycan (PG) precursors at the bacillary septum and poles, which suggest a possible deficiency in PG biosynthesis. Consequently, the cell wall becomes resistant to antibiotics, leading to multidrug resistance (MDR). In this study, bioinformatics analyses were performed on MDR-TB isolates from 24 clinical samples to search for novel mutations that contribute to antibiotic resistance. We found out a potential deletion of nucleotides encoding 6 amino acids in all 12 samples, particularly in fhaA gene (RV0020c). Our subsequent structural analysis shows that the deletion is at the position 243-248, causing conformational change of the native FhaA protein. We postulated that the deletion will potentially cause the loss of its binding affinity to MviN (precursor) and STPK (protein kinase), resulting in the inhibition and blockage of the peptidoglycan polymerization, causing MDR in MTB. In the future, experimental validation is necessitated to substantiate the association of these mutations with MDR.