<s>[INST] What is multidrug-resistant TB and how do we manage it? [/INST] Multidrug-resistant TB (MDR-TB) is classified as TB that does not respond to at least rifampicin and isoniazid – the two most powerful TB drugs. There are a number of ways in which MDR-TB can emerge and spread – including through the mismanagement or partial completion of TB treatment followed by person-to-person transmission of drug-resistant TB. Drug resistance can emerge due to the inappropriate or incorrect use of TB drugs, the use of ineffective drug formulations (such as single-drug formulations or formulations that use poor quality or badly stored medicines) and/or prematurely stopping treatment. MDR-TB can then be transmitted, especially in crowded settings such as prisons and hospitals. Most people with TB are cured only by strictly following a 6-month drug regimen with the required support and supervision. When this is not done correctly, the TB bacterium can develop resistance to the drugs being used to cure the disease.

In some countries, it is becoming increasingly difficult to treat MDR-TB. Treatment options are limited and expensive, with the recommended medicines not always available. In addition, patients may experience several adverse side-effects from the drugs. In some cases, even more severely drug-resistant TB strains may develop. However, testing for drug-resistant TB is becoming more effective due to the development of more-rapid WHO-recommended molecular diagnostic techniques. Such techniques (for example, Xpert MTB/RIF) can provide results within hours and have been successfully implemented even in low-resource settings. In addition, for many patients, treatment duration is now shorter than it used to be in the past, thus making it easier for patients to complete the whole course of treatment and increase the probability of a successful treatment outcome.

The new WHO guidance mentioned above aims to speed up detection and improve treatment outcomes for MDR-TB through the use of such molecular diagnostic testing and a shorter treatment regimen. At less than US$ 1000 per patient, this new regimen can be completed in 9–12 months for certain patients and patient groups. Not only is it less expensive than current regimens, but it is also expected to improve outcomes by improving adherence to treatment.

The main approaches to preventing or managing MDR-TB are:

to provide prompt access to services for the diagnosis of TB and drug-resistant TB;

to successfully treat the patient the first time around;

to ensure adequate infection prevention and control measures in facilities where patients are being treated; and

to ensure the appropriate use of recommended drugs for drug-resistant TB. Source: WHO. Link: https://www.emro.who.int/tuberculosis/faqs/index.html. Field: Lung Disease. Disease: Tuberculosis </s>