A Novel Rapid Detection Method for Mycobacterium tuberculosis Based on Scattering-Light Turbidity Using Loop-Mediated Isothermal Amplification.

Abstract

The accurate detection of Mycobacterium tuberculosis (MTB) is a pressing challenge in the precise prevention and control of tuberculosis. Currently, the efficiency and accuracy of drug resistance detection for MTB are low, and cross-contamination is common, making it inadequate for clinical needs. This study developed a rapid nucleic acid detection method for MTB based on scattering loop-mediated isothermal amplification (LAMP). Specific primers for the MTB-specific gene (Ag85B) were designed, and the LAMP reaction system was optimized using a self-developed scattering LAMP turbidimeter. Experimental results showed that the optimal reaction system included 1.5 µL of 100 mmol/L magnesium ions, 3.5 µL of 10 mmol/L dNTPs, 6 µL of 1.6 mol/L betaine, and a reaction temperature of 65 °C. The minimum detection limit was 12.40 ng/L, with the fastest detection time being approximately 10 min. The reaction exhibited good specificity, with no amplification bands for other pathogens. Twenty culture-positive samples and twenty culture-negative samples were tested in parallel; the accuracy of the positive group was 100%, the detection time was (24.9 ± 13 min), and there was no negative detection. This method features high detection efficiency, low cost, high accuracy, and effectively reduces cross-contamination, providing a new technology for the rapid clinical detection of MTB.