Classical against molecular-genetic methods for susceptibility testing of antituberculotics
I Porvaznik1, J Mokry, I Solovic
1National Reference Laboratory for Mycobacteria, National Institute of Tuberculosis, Pulmonary Diseases and Thoracic Surgery, 1 Vysne Hagy St., 059 84, Vysoke Tatry, Slovakia, porvaznik@hagy.sk.
Advances in Experimental Medicine and Biology
|September 26, 2014
Summary
Molecular-genetic testing offers rapid detection of multi-drug resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB). This faster diagnosis aids timely treatment and prevents the spread of resistant tuberculosis strains.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Molecular Diagnostics
Background:
- Tuberculosis (TB) remains a global health challenge, complicated by the rise of multi-drug resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB).
- Conventional diagnostic methods for TB drug resistance, relying on mycobacterial cultivation and susceptibility testing, are time-consuming and can delay appropriate patient treatment.
- The emergence of drug-resistant TB necessitates faster diagnostic approaches to guide effective therapeutic strategies and control disease transmission.
Purpose of the Study:
- To compare the efficacy of standard cultivation-based drug susceptibility testing with rapid molecular-genetic methods for diagnosing drug-resistant tuberculosis.
- To evaluate the utility of PCR-based diagnostic kits for identifying resistance to key anti-tuberculosis drugs, including isoniazid, rifampicin, ethambutol, aminoglycosides, and fluoroquinolones.
- To assess the role of molecular-genetic testing in the timely diagnosis and management of MDR-TB and XDR-TB cases.
Main Methods:
- Comparison of standard mycobacterial cultivation and drug susceptibility testing with molecular-genetic testing using PCR diagnostic kits.
- Analysis of Mycobacterium tuberculosis strains for resistance to isoniazid and rifampicin (MDR-TB markers).
- Genomic verification of resistance to ethambutol, aminoglycosides, and fluoroquinolones for XDR-TB characterization.
Main Results:
- Molecular-genetic testing provided rapid evidence of Mycobacterium tuberculosis and identified drug resistance.
- Resistance to rifampicin was consistently confirmed by both cultivation and molecular methods across all analyzed strains.
- Discrepancies were observed for isoniazid resistance (PCR negative, cultivation positive in two cases) and for ethambutol (two cases) and fluoroquinolones (five cases), where PCR identified resistance missed by conventional testing.
Conclusions:
- Molecular-genetic testing, particularly PCR-based methods, offers a significant advantage in the rapid diagnosis of drug-resistant tuberculosis.
- This technology enables swift identification of MDR-TB and XDR-TB strains, facilitating prompt and appropriate drug treatment.
- Rapid molecular diagnostics are crucial for preventing the further spread of drug-resistant tuberculosis strains and improving patient outcomes.
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