Types of drug-resistant tuberculosis

 

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Pulmonary tuberculosis (TB) is an airborne infectious disease that usually affects the lungs. The disease is caused by the bacteria Mycobacterium tuberculosis and is, according to the World Health Organization, the second greatest killer worldwide due to a single infectious agent.

Tuberculosis is treatable through a six-month course of first-line TB drugs.

Drug-resistant tuberculosis occurs when treatment is disrupted: the patient stops taking medication or does not complete the entire treatment period. Another common cause is the use of poor-quality anti-TB drugs. In drug-resistant tuberculosis, the levels of antibiotics in the patient’s body become insufficient to kill all of the TB-causing bacteria present and the remaining bacteria become resistant to medication.

There are two types of drug-resistant tuberculosis:

Multidrug-Resistant Tuberculosis (MDR-TB)

MDR-TB occurs when the TB-causing bacteria becomes resistant to isoniazid and rifampin, the two most common first-line drugs used to treat TB. MDR-TB is more difficult to treat than drug-responsive TB. Treatment usually involves combination therapy with second-line drugs that should be taken for two years or more. Drugs for MDR-TB often have severe side effects such as depression, hepatitis, and deafness.

 

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Extensively drug-resistant TB (XDR-TB)

In XDR-TB, the TB-causing bacteria have changed and are immune to isoniazid and rifampin,
as well as fluoroquinone and at least one of three second-line drugs like capreomycin and amikacin. XDR-TB has a higher mortality rate than drug-responsive TB and MDR-TB. Patients with compromised immune systems have a higher risk of death from complications of XDR-TB.

Totally drug-resistant TB (TDR-TB)

TDR-TB refers to tuberculosis strains that are resistant to all first and second-line anti-TB medication. Although the term “TDR-TB” is not recognized by the WHO, which questions the necessity of creating a new diagnostic definition, cases of TB that are resistant to all known anti-TB drugs have been reported in South Africa, India, China, and Italy.

 

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To prevent developing drug-resistant tuberculosis, TB patients should take their medication as prescribed and report any difficulties in taking or obtaining the necessary drugs to their doctors.

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