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Updated: May 25, 2026
07:35
Demonstrating a Multi-drug Resistant Mycobacterium tuberculosis Amplification Microarray
Published on: April 25, 2014
GenoType MTBDRsl performance on clinical samples with diverse genetic background
Paolo Miotto1, Andrea M Cabibbe, Paola Mantegani
1Emerging Bacterial Pathogens Unit, Division of Immunology, Transplantation and Infectious Diseases, San Raffaele Scientific Institute, Via Olgettina 58, 20132 Milano, Italy.
The European Respiratory Journal
|January 24, 2012
Summary
The GenoType® MTBDRsl test shows high specificity for detecting second-line drug resistance in tuberculosis, but requires confirmation for negative results due to variable sensitivity. Mutations in the rrs gene are linked to the Beijing lineage.
Area of Science:
- Microbiology
- Molecular Diagnostics
- Infectious Diseases
Background:
- Tuberculosis (TB) drug resistance poses a significant global health challenge.
- Accurate and rapid detection of resistance to second-line drugs is crucial for effective treatment regimens.
- Understanding the correlation between genetic mutations and drug resistance patterns is essential for TB control.
Purpose of the Study:
- To evaluate the performance of the GenoType® MTBDRsl assay for detecting second-line drug resistance in Mycobacterium tuberculosis.
- To correlate the frequency of specific mutations with different Mycobacterium tuberculosis genotypes.
- To assess the diagnostic accuracy of the MTBDRsl assay on clinical isolates and respiratory specimens.
Main Methods:
- Performance evaluation of the GenoType® MTBDRsl assay on 175 M. tuberculosis strains and 59 clinical specimens.
- Interpretation of results following Standards for Reporting of Diagnostic Accuracy (STARD) recommendations.
- Genotyping of strains using spoligotyping and Mycobacterial Interspersed Repetitive Units-Variable Number of Tandem Repeats (MIRU-VNTR) typing.
Main Results:
- The MTBDRsl assay demonstrated high specificity (∼99%) and positive predictive value (PPV, ∼99%) for detecting resistance to fluoroquinolones (FQ), second-line injectable drugs (SLID), and ethambutol (EMB).
- Sensitivity for FQ resistance was 100%, while for SLID and EMB it was approximately 86-89%.
- A significant association was found between rrs gene mutations and the Beijing lineage of M. tuberculosis.
Conclusions:
- The GenoType® MTBDRsl assay is valuable for "ruling in" extensively drug-resistant tuberculosis strains in high-risk populations.
- Low sensitivity and negative predictive value (NPV) necessitate confirmation by conventional drug susceptibility testing when mutations are absent.
- The predictive values of molecular tests are influenced by the genetic background, with higher NPV for SLID in Beijing strains.
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