Rapid and Visual Detection of Mycobacterium tuberculosis Complex Based on Multiplex Recombinase Polymerase Amplification

Abstract

Background

Tuberculosis (TB) remains a leading cause of mortality worldwide, particularly in developing nations. Currently, available diagnostic methods are often too costly or insufficiently sensitive for effective use in low- and middle-income countries. Developing a rapid, convenient, and accurate method for detecting the Mycobacterium tuberculosis complex (MTBC) is crucial to curtail the spread of TB.

Methods

Primers and probes targeting conserved regions of IS1081 were designed, and the RNase P gene was introduced as an internal control to prevent false-negative results. M. tuberculosis control was used to optimize the reaction temperature. Additionally, we calculated and compared the limit of detection, specificity, and coincidence rate between this platform and the TaqMan real-time fluorescence quantification method (RT-qPCR) using two sets of national reference panels and 10 strains of MTBC.

Results

An on-site MTBC-multiplex recombinase polymerase amplification (MTBC-mRPA) platform was established, with detection within 30 min over a broad temperature range (25°C–45°C). Probit analysis estimated a 95% limit of detection of 557.16 (95% confidence interval: 406.76–1062.67) bacteria/mL (p < 0.0001), close to the limit of detection of 461.84 (95% confidence interval: 342.55–881.57) bacteria/mL (p < 0.0001) of qPCR. The platform differentiated between non-tuberculous mycobacteria and other common respiratory bacteria, showing 100% specificity. The coincidence rate between multiplex real-time recombinase polymerase amplification (RT-mRPA) and RT-qPCR was 100%, indicating substantial similarity.

Conclusion

A simple, rapid, and visual MTBC-mRPA platform coupled with rapid DNA extraction was developed for sensitive and specific detection of MTBC, especially suitable for on-site screening of TB in low-resource settings.