Two Years of Retrospective Study on the Incidence of Tuberculosis in Dir Lower Valley, Khyber Pakhtunkhwa, Pakistan

Distribution of common and rare drug resistance patterns in Mycobacterium tuberculosis clinical isolates revealed by GenoType MTBDRplus and MTBDRsl assay

Background

Tuberculosis (TB) remains a significant global health emergency caused by Mycobacterium tuberculosis (Mtb). The epidemiology, transmission, genotypes, mutational patterns, and clinical consequences of TB have been extensively studied worldwide, however, there is a lack of information regarding the epidemiology and mutational patterns of Mtb in Pakistan, specifically concerning the prevalence of multi-drug resistant TB (MDR-TB).

Methods

This study aimed to investigate the incidence of Mtb and associated mutational patterns using the line probe assay (LPA). Previous studies have reported a high frequency of mutations in the rpoB, inhA, and katG genes, which are associated with resistance to rifampicin (RIF) and isoniazid (INH). Therefore, the current study utilized LPA to detect mutations in the rpoB, katG, and inhA genes to identify multi-drug resistant Mtb.

Results

LPA analysis of a large pool of Mtb isolates, including samples from 241 sputum-positive patients, revealed that 34.85% of isolates were identified as MDR-TB, consistent with reports from various regions worldwide. The most prevalent mutations observed were rpoB S531L and inhA promoter C15T, which were associated with resistance to RIF and INH, respectively.

Conclusions

This study highlights the effectiveness of GenoType MTBDRplus and MTBDRsl assays as valuable tools for TB management. These assays enable rapid detection of resistance to RIF, INH, and fluoroquinolones (FQs) in Mtb clinical isolates, surpassing the limitations of solid and liquid media-based methods. The findings contribute to our understanding of MDR-TB epidemiology and provide insights into the genetic profiles of Mtb in Pakistan, which are essential for effective TB control strategies.