Conventional DNA Extraction Followed by Real-Time PCR Had Higher Sensitivity for Detection of Mycobacterium Tuberculosis in Clinical Samples Compared to Standard Methods.

Abstract

The Mycobacterium tuberculosis complex (MTBC), the causative agent of tuberculosis (TB), remains a significant global health challenge, with an estimated 10.8 million cases diagnosed and 1.25 million deaths in 2023, according to the WHO. In this context, enhancing TB case detection using more sensitive diagnostic methods is essential. Here, we compared the performance of two commercial real-time polymerase chain reaction (PCR) kits with the reference standards of smear microscopy, culture, and Gene Xpert. By analyzing 402 clinical specimens, we found that conventional DNA extraction, followed by real-time PCR, using either of the two commercial kits provided the highest sensitivity for detecting MTBC. Positivity values of 48.98-60.07% and 50.34-53.24% were obtained with the commercial kits "VIASURE MTBC + non tuberculous mycobacterias (NTM) Real-Time PCR Detection Kit" (Certest, Spain) and "ANYPLEX™ MTB/NTM Real-Time Detection Kit" (Seegene, South Korea), respectively. In contrast, the reference standards yielded positivity values of 14.75% (smear microscopy), 32.65% (culture), and 28.95% (GeneXpert assay). These alternative methods should be considered as valuable tools to strengthen TB control and prevention strategy.