Tuberculosis (TB) is a global health problem caused by the Mycobacterium tuberculosis complex (MTBC). These bacteria secrete various proteins involved in the pathogenesis and persistence of MTBC. Among the secretory proteins, MPT64 (Rv1980C) is highly conserved and is also known as a major culture filtrate that is used in rapid diagnosis of MTBC. In the current study, we aimed to find the mutation in this highly conserved protein in isolates from the Pashtun-dominant province of Pakistan. We analyzed 470 M. tuberculosis whole-genome sequences of Khyber Pakhtunkhwa Province. Mutations in the MPT64 gene were screened through TB-Profiler and BioEdit software tools. The DynaMut web server was used to analyze the impact of the mutation on protein dynamics and stability. Among 470 MTB genomes, three non-synonymous mutations were detected in nine isolates, and one synonymous mutation (G208A) was found in four isolates. Mutation G211T (F159L), which was detected at the C-terminal domain of the protein in six isolates, was the most prominent. The second novel mutation, T480C (I70V), was detected in two isolates at the C-terminal side of the protein structure. The third novel mutation, A491C (L66R), was detected in a single isolate at the N-terminal side of the MPT64 protein. The effect of these three mutations was destabilizing on the protein structure. The molecular flexibility of the first two mutations increased, and the last one decreased. MPT64 is a highly conserved secretory protein, harboring only a few mutations. This study provides useful information for better managing the diagnosis of MTB isolates in high TB-burden countries.

Tuberculosis (TB), caused by bacteria of the Mycobacterium tuberculosis complex (MTBC), remains a global health challenge, exacerbated by multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains. This study employs whole-genome sequencing (WGS) to characterise genetic mutations associated with pyrazinamide (PZA) and fluoroquinolone (FQ) resistance in MDR-TB isolates from KPK. MDR and pre-XDR TB samples were collected and processed at the Provincial Tuberculosis Reference Laboratory under Biosafety Level III conditions. Samples underwent microscopy, GeneXpert MTB/RIF assay, culture, and drug susceptibility testing. DNA was extracted from positive cultures and subjected to WGS. Bioinformatics tools were used to analyse sequencing data, identify resistance-associated mutations, and assess genetic diversity among isolates. Out of the 78 MTBC isolates analysed, 67 (85.9 %) were identified as MDR-TB, with 48 categorized as pre-XDR, while 11 were drug-susceptible. The isolates predominantly came from young patients (mean age: 29.5 years, SD ±12.64), with a higher proportion of female patients (61.53 %). Mutations in the pncA gene, associated with PZA resistance, were identified in 51 isolates. Resistance to fluoroquinolones was linked to mutations in the gyrA and gyrB genes in 48 isolates. WGS confirmed PZA resistance in 51 isolates, 39 (76.47 %) of which also exhibited FQ resistance. Phylogenetic analysis revealed that Lineage 3 (L3) was predominant (58.97 %), followed by L4, L2, and L1 strains. The clustering of drug-resistant strains within L3 suggests ongoing localized transmission. These findings underscore the urgent need for targeted interventions, including enhanced molecular surveillance and tailored treatment strategies, to combat MDR-TB in KPK.