Advancement in the Molecular Diagnosis of Tuberculosis

Mycobacterium tuberculosis (MTB) is an airborne infectious disease that causes tuberculosis (TB), which affects mainly the lungs. Eighty percent of all cases of tuberculosis are pulmonary (PTB). The extrapulmonary form of tuberculosis (EPTB) can affect the colon, meninges, lymph nodes, bones, joints, kidneys, and skin. Depending on the response of the host immune system, exposure to MTB bacilli results in eradication or persistence of the pathogen [1]. TB is the most prevalent infectious cause of mortality in adults’ worldwide [2]. According to WHO India represents one-fifth of the global burden of TB. Early and accurate diagnosis is crucial for disease management and improved patient outcomes. With the advent of more recent microscopy, culture, and molecular techniques, diagnostic modalities for tuberculosis have improved significantly over the past few decades. For the purpose of determining a diagnosis, monitoring treatment and stopping the spread of tuberculosis, improved laboratory techniques are essential. In contrast to traditional culture systems, which take several weeks to diagnose TB, molecular detection offers quicker and more affordable ways to identify and confirm resistance to treatment in TB cases. New developments in the molecular diagnosis of tuberculosis, such as the quicker and easier nucleic acid amplification test (NAAT) and whole-genome sequencing (WGS), have sped up the diagnosis and, consequently, TB treatments [3]. There are new methods for improving culture medium, such as culture system improvement, early growth detection, strict oxygen tension control, and MALDI-TOF-MS (matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry) for identification [4]. Most molecular tests have focused on identifying specific nucleic acids to MTB, both in DNA and RNA, using amplification techniques such as polymerase chain reaction (PCR) and identifying gene mutations associated with drug resistance through sequencing or nucleic acid hybridisation [5].