Validation of the FluoroType^® MTBDR assay using respiratory and lymph node samples.

Area of Science:

• Microbiology
• Molecular Diagnostics
• Infectious Diseases

Background:

• Tuberculosis (TB), particularly drug-resistant strains, poses a significant global health challenge.
• Accurate and rapid molecular diagnostic tests are essential for effective TB control.
• The FluoroType® MTBDR is a novel molecular assay developed for TB diagnosis.

Purpose of the Study:

• To validate the performance of the FluoroType® MTBDR assay for the detection of Mycobacterium tuberculosis complex (MTBC).
• To compare the sensitivity and specificity of FluoroType® MTBDR with the Genotype MTBDRplus assay.
• To assess the utility of FluoroType® MTBDR in identifying drug resistance.

Main Methods:

• Samples included respiratory (n=350) and lymph node (n=59) specimens.
• DNA extraction was performed using the Fluorolyse® kit.
• Samples were tested with FluoroType® MTBDR and Genotype MTBDRplus assays.

Main Results:

• FluoroType® MTBDR demonstrated high sensitivity for MTBC DNA detection: 91.4% in respiratory and 62.5% in lymph node samples.
• Sensitivity for detecting rifampicin (RMP) and isoniazid (INH) resistance was 96.5% and 70% respectively in respiratory samples.
• A notable proportion of indeterminate results were observed for rpoB, katG, and inhA genes (20.3%–35.9%).

Conclusions:

• The FluoroType® MTBDR assay exhibits high sensitivity for detecting MTBC DNA.
• The assay shows promise in identifying drug resistance associated with TB.
• The high rate of indeterminate results necessitates further optimization of the FluoroType® MTBDR assay.