TGS / TB Whole Genome Sequencing

Tuberculosis or TB, caused by the bacterium Mycobacterium tuberculosis (MTB) is one of the diseases with a high fatality rate that mostly affects the lungs (Pulmonary TB) and sometimes infects other parts of the body like pleura, joints, abdomen, skin, etc (Non-pulmonary TB). The disease spreads mainly when the bacteria are dispersed in the air when an infected person spits, coughs, or sneezes. Due to the slow growth pattern and drug resistance, the disease presents a major challenge in terms of treatment and quick diagnostic techniques.

The development of resistance against drugs in MTB signifies that the particular drug is no longer effective against the bacterium and cannot be used in treating the infection. Tuberculosis- Whole Genome Sequencing (TGS/TB WGS) is a highly sensitive technique that analyses the genome of MTB. It helps in early detection of infection with multidrug-resistant MTB for better-individualized treatment with correct antibiotics at the right time.

Cough for more than three weeks, chills, fever, night sweats, loss of appetite, weakness, and weight loss are some of the symptoms observed in individuals suffering from TB infection.

Why Get Tested with TGS / TB Whole Genome Sequencing?
TGS / TB Whole Genome Sequencing test is a sequencing technique that analyses the genome of Mycobacterium tuberculosis, the bacterium that is responsible for Tuberculosis and helps in identifying infection with drug-resistant strains.

What sample is required and what preparation is needed for this test?
A number of samples including body fluids, sputum, bronchial alveolar lavage, cerebrospinal fluid (CSF), pus, tissue, biopsies, lymph nodes, abscess, urine can be used for performing this test. There is no special preparation required before getting this test.

What are the types of drug-resistant TB?
Drug-resistant tuberculosis infection, caused by drug-resistant Mycobacterium tuberculosis (MTB) bacterium is divided into the following categories

• Multidrug-resistant or MDR-TB: MDR-TB is the TB infection caused by MTB that is resistant to the most potent drugs used in TB treatment – isoniazid and rifampin.
• Extensively drug-resistant or XDR-TB: XDR-TB is the TB infection caused by MTB that is resistant to most commonly used drugs used in TB treatment like isoniazid and rifampin, plus any fluoroquinolone as well as at least one of the three injectable second-line drugs (amikacin, kanamycin, and capreomycin).

Is there any vaccine for Tuberculosis? Can TB be cured?
Bacille Calmette-Guérin (BCG) is the vaccine available for prevention of TB infection. TB is a preventable and curable disease. Active infections can be treated with a 6-month course of antimicrobial drugs.

What can be understood by TGS / TB Whole Genome Sequencing?
TGS / TB Whole Genome Sequencing technique gives a sequence of the genome of Mycobacterium tuberculosis, the bacterium responsible for Tuberculosis. Genetic information aids in-

• Differentiating between different strains of the bacteria
• Determining if the TB disease is due to recent exposure/transmission
• Determination of drug resistance