What are multi-drug resistant TB (MDR-TB) and extreme drug resistant TB (XDR-TB)?
When a strain of tuberculosis bacteria is resistant to two or more ‘first-line’ antibiotic drugs it is called multi-drug resistant TB or MDR-TB. When it is resistant to three or more ‘second-line’ antibiotics as well, it is classed as extreme drug resistant tuberculosis, or XDR-TB. Drug resistance usually arises when tuberculosis patients do not or cannot take their medicine as prescribed, and drug-resistant mutations of the bacteria are allowed to replicate. People can also catch MDR and XDR-TB from others. MDR-TB is a serious problem and is very difficult to treat. In normal treatment (sometimes referred to as ‘first-line’ treatment) for tuberculosis, patients take the drugs isoniazid and rifampicin (the most effective tuberculosis drug available) plus other drugs for around six to eight months. If a person is resistant to isoniazid and rifampicin however, they are said to have MDR-TB, and will need to change to a regime containing newer and often less widely-available ‘second-line’
