Antibiogram – MTB (Isoniazid)

Tuberculosis or TB, caused by Mycobacterium tuberculosis (MTB) is one of the diseases with a high fatality rate that mostly affects the lungs (Pulmonary TB) and sometimes affects other components like pleura, joints, abdomen, skin, etc (Non-pulmonary TB). The disease spreads 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.

Antibiogram test or Antimicrobial Susceptibility testing is performed to measure the susceptibility of microbes to certain antibiotics. Antibiogram MTb (Isoniazid) test checks for the sensitivity or resistance of MTB to Isoniazid drug. Isoniazid is the first-line anti-TB drug, it is used to treat and prevent tuberculosis. It is given in combination with other drugs while treating active TB.

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 and When to get Tested with Antibiogram MTb Isoniazid?
Antibiogram MTb (Isoniazid) test checks for the sensitivity or resistance of Mycobacterium tuberculosis to Isoniazid drug. This test is needed if an infection has shown to have antibiotic resistance or is otherwise hard to treat. Or if there’s a bacterial or fungal infection that is not responding to standard treatments.

What is an Antibiogram test?
Antibiogram test or Antibiotic susceptibility testing (AST) is a widely-used technique for evaluating antibiotic resistance and determining the most effective antibiotic for treatment. This is achieved by observing the effect of a particular antibiotic on microbial growth. The treatment can be directed as per the knowledge of the microbe and its sensitivity to the drug.

What sample is required and what preparation is needed for this test?
A pure culture obtained from body fluids, sputum, bronchial alveolar lavage, cerebrospinal fluid (CSF), pus, tissue, biopsies, lymph nodes, abscess, and urine is 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: 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).

What is the role of Isoniazid in Tuberculosis treatment?
Isoniazid is used to treat active infection with TB, it is also used to prevent active infection in people infected with MTB, it works by stopping the growth of bacteria.