Multi-drug resistant gene mutation analysis in Mycobacterium tuberculosis by molecular techniques

Area of Science:

• Molecular biology
• Microbiology
• Infectious diseases

Background:

• Tuberculosis (TB) treatment relies on antibiotics like rifampicin (RIF) and isoniazid (INH).
• Multidrug-resistant tuberculosis (MDR-TB) arises from Mycobacterium tuberculosis strains resistant to these first-line drugs.
• Rapid identification of MDR-TB is crucial for effective treatment and control.

Purpose of the Study:

• To evaluate the efficacy of PCR sequencing and GeneXpert assay for rapid MDR-TB detection.
• To identify specific gene mutations associated with RIF and INH resistance in Mycobacterium tuberculosis.
• To compare the diagnostic performance of molecular methods with culture-based drug susceptibility testing (DST).

Main Methods:

• Sputum samples from 55 MDR-TB suspected patients were analyzed.
• PCR sequencing and GeneXpert assay were used to detect mutations in the rpoB and katG genes.
• Culture-based drug susceptibility testing (DST) was performed for comparison.

Main Results:

• Sequencing identified rpoB gene mutations in 80% of samples (codon 531: 54.54%, 526: 14.54%, 516: 10.91%).
• katG gene mutations (G315) were found in 76.19% of tested samples.
• PCR sequencing demonstrated high sensitivity and specificity for RIF (98%, 100%) and INH (94%, 100%) resistance, while GeneXpert showed 85.45% accuracy for RIF mono-resistance.

Conclusions:

• PCR sequencing is an efficient tool for rapid MDR-TB detection.
• The method offers high sensitivity and specificity, with shorter turnaround times.
• Supports the adoption of PCR sequencing for improved MDR-TB diagnosis and management.