Rapid diagnosis of pyrazinamide-resistant multidrug-resistant tuberculosis using a molecular-based diagnostic...

Area of Science:

• Microbiology
• Genetics
• Infectious Diseases

Background:

• Multidrug-resistant tuberculosis (MDR-TB) poses a significant global health challenge.
• Rapid and accurate diagnostics for pyrazinamide-resistant MDR-TB are urgently needed.
• Current diagnostic algorithms for pyrazinamide resistance in MDR-TB are not well-validated.

Purpose of the Study:

• To evaluate the accuracy of pncA gene sequencing combined with rpoB mutation analysis for identifying pyrazinamide-resistant MDR-TB.
• To establish a validated diagnostic algorithm for pyrazinamide resistance in MDR-TB cases.

Main Methods:

• Prospective sequencing of the pncA gene in Mycobacterium tuberculosis isolates with known rpoB mutations.
• Comparison of molecular analysis results (rpoB and pncA mutations) with phenotypic drug susceptibility testing (DST) for rifampicin, isoniazid, and pyrazinamide.
• Utilized the Mycobacterial Growth Indicator Tube 960 system for phenotypic DST.

Main Results:

• Analysis included 83 clinical M. tuberculosis isolates with rpoB mutations; 78% were MDR-TB.
• Phenotypic DST identified pyrazinamide resistance in 48% of MDR-TB isolates.
• pncA sequencing added to rpoB mutation analysis demonstrated high sensitivity (96.8%) and specificity (94.2%) for detecting pyrazinamide-resistant MDR-TB.

Conclusions:

• pncA sequencing combined with rpoB mutation analysis provides an accurate method for detecting pyrazinamide-resistant MDR-TB.
• This molecular approach can aid in stratifying MDR-TB treatment based on pyrazinamide susceptibility.
• The study proposes integrating pncA sequencing into routine diagnostics for MDR-TB isolates with rpoB mutations.