[Molecular technologies in detecting sensitive and isoniazid-resistant Mycobacterium tuberculosis]

Area of Science:

• Molecular Biology
• Genetics
• Microbiology

Context:

• Isoniazid resistance in Mycobacterium tuberculosis (MTB) is a significant global health concern.
• Point mutations in the 315 codon of the katG gene are strongly associated with isoniazid resistance.
• Accurate and rapid detection of these mutations is crucial for effective tuberculosis treatment.

Purpose:

• To develop and characterize novel PCR-based techniques for detecting specific single nucleotide polymorphisms (SNPs) in the MTB katG gene.
• To differentiate between wild-type and isoniazid-resistant MTB strains based on katG gene mutations.

Summary:

• Two distinct PCR techniques were developed for SNP detection in the 315 codon of the MTB katG gene.
• The first technique utilizes two primer sets with a competitive blocking primer to identify specific mutations (AGC --> ACC and AGC --> AGA).
• The second technique employs a primer set with LNA-monomers to detect any of the six known mutations, enabling differentiation of wild-type from resistant strains.

Impact:

• These methods offer improved diagnostic capabilities for isoniazid-resistant MTB.
• The developed techniques contribute to the rapid identification of drug-resistant tuberculosis strains.
• Characterization of primer purity and structure using MALDI-mass spectrometry ensures assay reliability.