**17. Available treatment**

*Molecular Epidemiology Study of Mycobacterium Tuberculosis Complex*

these drawbacks of antibiotics (**Table 2**).

GeneXpert, line prob. assay, LAMP assay etc.

**16.1 GeneXpert**

**16.2 Line probe assay (LPA)**

features\_archive/TB\_LAMP/en/).

some of the side effects and the present major challenge to researchers to overcome

**16. Recent developments in diagnostic approaches for tuberculosis**

It is not easy to conduct a clinal diagnosis of tuberculosis very frequently as confirmed diagnosis requires culturing the bacteria *M. tuberculosis* in a sample from the patient [5] and which is very slow-growing. For lung diseases, we take morning sputum for culture purpose and microscopic studies. We also have to do Biopsies of the affected tissues, because that will provide us with a sample for culture and also for looking histologically for the characteristic presence of granulomas [53]. Mycobacterial culture confirms the presence of mycobacterium in given samples by microscopy analysis, and we may also draw the resistance profile i.e., whether the present strain belongs to the sensitive *M. tuberculosis* group or has resistance to some drugs that can be used to treat it. The major obstacles in culture MTB are that it is slow-growing bacteria and may take 3–4 weeks in liquid culture media [51]. The acid-fast bacilli of mycobacterial infection are detected by the microscopy analysis whereas latent tuberculosis disease is identified by immunological responses to tuberculosis antigens, i.e., i) Heaf test / Montoux: cofounded by BCG ii) Interferon Gamma Release Assays (IGRA) [48, 49]. There are some tools developed recently for the detection of drug-resistant MTB that facilitates early detection too, such

GeneXpert can detect mutations that cause resistance against Rifampicin. The test is a molecular TB test that detects the DNA of *Mycobacterium tuberculosis*. It uses a sputum sample and thus provides result in less than 2 hours. It can also detect the genetic mutations which are associated with drug Rifampicin resistance [65]. WHO recommended that this test should be used as the primitive diagnosis test in individuals suspected of having Multi-drug resistant TB, or HIV associated TB.

This technique also helps to detects mutations causing resistance against Rifampicin. Moreover, this assay can also detect mutations related to drug isoniazid [66]. The line probe assay (LPA), is typically based on strip technology and thus is used in the diagnosis of TB. It also detects RIF as well as Isoniazid (INH) resistance

WHO has recommended the TB-LAMP (loop-mediated isothermal amplification) test that requires minimal laboratory infrastructure and has been evaluated as an alternative to sputum smear microscopy, which remains the most widespread test used in resource-limited environments. TB-LAMP is a unique temperatureindependent way to amplify the DNA of tuberculosis patients. It is a manual test that takes less than one hour and results can be visualized with the naked eye under UV light. The potent TB-LAMP instrument can be used at the level of the peripheral health center where microscopy is often performed. (https://www.who.int/tb/

caused due to mutations in *rpo*β, and both *inhA* and *katG* genes.

**16.3 Loop-mediated isothermal amplification (LAMP) assay**

**22**

At present treatment of tuberculosis requires more than one antibiotic with prolonged combination therapies to eradicate the infection and prevent resistance [58] and the standard therapy may include 4 antibiotics i.e., Isoniazid & Rifampicin (most effective drugs and these are given for six months and thus these two helps in killing the bacteria), Pyrazinamide & Ethambutol (given for first two months only) [67, 68]. During treatment antibiotics are required for a long period, the minimum treatment period is six months and if the patient is having CNS or bone disease it often goes on for at least 12 months [69]. The patient is asked to take four drugs for two months and then followed by two drugs for four months, and the actual dose given to the patient is decided by their body weight such as if a patient is lower than 50 kg, they get a lower dose while if the patient is above 50 kg, they get a higher dose [13].

Corticosteroids are given to patients with CNS or pericardial disease because this reduces the further chances of having long term brain damage. All the cases need to be monitored and notified so that there can be a screening process of the patient's close contacts as well [14, 17].
