What is multidrug-resistant tuberculosis and how do we control it?

Online Q&A
Reviewed March 2014

Q: What is multidrug-resistant tuberculosis and how do we control it?

A: The bacteria that cause tuberculosis (TB) can develop resistance to the antimicrobial drugs used to cure the disease. Multidrug-resistant tuberculosis (MDR-TB) is TB that does not respond to at least isoniazid and rifampicin, the two most powerful anti-TB drugs.

The primary causes of multidrug resistance are mismanagement of TB treatment and person-to-person spread. Most people with tuberculosis are cured by a strictly followed, six-month drug regimen that is provided to patients with support and supervision. Inappropriate or incorrect use of antimicrobial drugs, or use of ineffective formulations of drugs, and premature treatment interruption can cause drug resistance, which can then be transmitted, especially in crowded settings such as prisons and hospitals.

In some countries, it is becoming increasingly difficult to treat MDR-TB. Treatment options are limited and expensive, recommended medicines are not always available, and patients experience many adverse effects from the drugs. In some cases even more severe drug-resistant tuberculosis may develop. Extensively drug-resistant TB, XDR-TB, is a form of multi-drug resistant tuberculosis that responds to even fewer available medicines. It has been reported in 92 countries worldwide.

Solutions to control drug-resistant TB are to:

  • cure the TB patient the first time around;
  • ensure adequate infection control in facilities where patients are treated;
  • ensure the appropriate use of recommended second-line drugs to treat this form of TB.

In 2012, an estimated 450 000 people developed MDR-TB in the world. It is estimated that about 9.6% of these cases were XDR-TB.