TB XDR Screen (LPA)

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.

Extensively drug-resistant TB  or XDR-TB is a rare form of TB caused by multidrug-resistant TB (MDR-TB) bacteria that are resistant to several effective anti-TB drugs like isoniazid and rifampin with any fluoroquinolone and at least one of the three injectable second-line drugs- amikacin, capreomycin or kanamycin. MDR-TB is caused by bacteria that are resistant to at least isoniazid or rifampicin. XDR-TB and MDR-TB strains have risen due to mismanagement of patient treatment.

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 TB XDR Screen (LPA)?
TB XDR Screen (LPA) test is a technique for rapid diagnosis of extensively drug-resistant Tuberculosis infection (bacteria that are several effective anti-TB drugs like isoniazid and rifampin with any fluoroquinolone and at least one of the three injectable second-line drugs- amikacin, capreomycin or kanamycin) for better individualized treatment.

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 is the technique used for the detection of multidrug-resistant bacteria in the TB XDR Screen?
TB XDR Screen (LPA) uses the Line Probe Assay (LPA) technique. LPA is a robust technique for the diagnosis of drug-resistant TB, thus providing rapid and effective control of drug-resistant cases. This test uses DNA strip technology and has three steps:

• DNA extraction
• Multiplex PCR amplification
• Reverse Hybridization

What are the causes of drug resistance in TB bacteria?

• Misuse or mismanagement of TB drug
• Incomplete treatment course
• Wrong treatment (drug dose or period)
• Unavailability of proper drugs
• Poor drug quality