Novel real-time simultaneous amplification and testing method to accurately and rapidly detect Mycobacterium...

Area of Science:

• Clinical microbiology
• Molecular diagnostics
• Infectious disease research

Background:

• Tuberculosis (TB) diagnosis relies on culture-based methods, which are time-consuming.
• Rapid and accurate detection of Mycobacterium tuberculosis is crucial for effective patient management and disease control.

Purpose of the Study:

• To develop and evaluate a novel, rapid simultaneous amplification and testing assay for Mycobacterium tuberculosis complex (SAT-TB assay).
• To assess the performance of the SAT-TB assay in clinical specimens using isothermal RNA amplification and real-time fluorescence detection.

Main Methods:

• The SAT-TB assay utilizes isothermal RNA amplification with Moloney murine leukemia virus (M-MLV) reverse transcriptase and T7 RNA polymerase.
• Real-time fluorescence detection is employed using a specific probe (FAM-DABCYL) to monitor amplification of a 170-bp M. tuberculosis 16S rRNA fragment.
• The assay was evaluated using clinical specimens and compared against the Bactec MGIT 960 culture assay.

Main Results:

• The SAT-TB assay demonstrated a sensitivity of 100 CFU/ml for M. tuberculosis H37Rv and showed no cross-reactivity with other mycobacteria or respiratory pathogens.
• Results from 387 clinical specimens showed 95.6% correlation with the Bactec MGIT 960 culture assay.
• For pulmonary TB diagnosis, the SAT-TB assay achieved 67.6% sensitivity and 100% specificity, outperforming Bactec MGIT 960 in smear-negative cases (39.2% vs. 30.2%).

Conclusions:

• The SAT-TB assay is a novel, rapid, and highly specific method for detecting Mycobacterium tuberculosis complex.
• This simple assay shows promise for enhancing TB detection rates and facilitating rapid diagnosis in clinical microbiology laboratories.
• The SAT-TB assay offers a valuable alternative or adjunct to traditional culture methods, particularly for smear-negative samples.