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MDR-TB – What is MDR-TB? how you get MDR-TB, RR-TB

What is MDR-TB?

MDR-TB is an abbreviation of Multi Drug Resistant TB and it is a particular type of drug resistant TB. It means that the TB bacteria that a person is infected with, are resistant to two of the most important TB drugs, isoniazid (INH) and rifampicin (RMP). If bacteria are resistant to certain TB drugs this means that the drugs won’t work. Other drugs then need to be taken by the person if they are to be cured of TB.

What is RR-TB?

For many years MDR-TB has been the most basic form of drug resistant TB, and the type of TB for which many statistics were collected. Then in 2016 RR-TB started to become more widely discussed because many people are now being diagnosed with TB using the GeneXpert test, which also detects resistance to rifampicin.

People with RR-TB are resistant to rifampicin, with or without resistance to other drugs. MDR/RR-TB means patients with MDR-TB as well as patients with TB resistant to rifampicin.

How do you get MDR-TB or RR-TB?

There are two main ways that you can get MDR TB or RR-TB. Firstly you can get it if you don’t take your drugs exactly as you have been instructed to by your health care provider. You may also get it if you are not taking the correct drugs. This could possibly be because your bacteria are resistant to more drugs than your health care provider realised. Maybe you have undiagnosed XDR-TB. This is referred to as acquired TB.

You can also get MDR or RR-TB if you become infected with TB bacteria from another person who already has MDR or RR-TB. This is known as primary TB. It used to be believed that most people have acquired TB, but now it is realised that many more people have primary TB.

How many people have MDR-TB?

Number of estimated MDR TB cases in 2014

Globally in 2015 there were about 480,000 people estimated to have become ill with MDR-TB. In addition there were an estimated additional 100,000 people who had rifampicin TB (RR-TB).  So the total number of people estimated to have had MDR-TB or RR-TB was 580,000 in 2015 .

MDR-TB accounts for about 3.3% of new TB cases.  Also, about 3.9% of new, and about 21% of previously treated TB cases were estimated to have either rifampicin or multi drug resistant TB in 2015.

About 9.5% of MDR-TB cases in 2015 had additional drug resistance, which means that they may have what is known as extensively drug resistant TB (XDR).

In 2015 MDR-TB and RR-TB caused approximately 250,000 deaths.

Detection of cases of MDR-TB

There is a large difference between the number of patients estimated to have had MDR-TB or RR-TB (580,000), and the number of people actually reported (notified) to WHO (132,000). In 2015 only 30% of the TB patients notified globally to WHO were tested for MDR-TB or RR-TB, although this was an improvement on the 22% tested in 2014. The notification numbers among different WHO regions for 2015 are shown in the table below.

Regional notification TB statistics

Notified WHO Regional MDR-TB & RR-TB statistics for 2015
Region Total notified MDR-TB & RR-TB cases notified
Africa 1,333,504 26,929
Americas 230,519 4,489
Eastern Mediterranean 484,733 4,081
Europe 297,448 42,646
South-East Asia 2,656,560 35,953
Western Pacific 1,361,430 18,022
Global Total 6,364,194 132,120

Enrollment on MDR Treatment

A total of 125,000 patients were enrolled on MDR-TB treatment in 2015 (up from 111,000 cases in 2014). However, this represents only about 22% of the estimated incident MDR/RR-TB cases in 2015. The gap between detected MDR/RR-TB cases and enrollments on treatment does though appear to have narrowed over time.

How do you treat MDR-TB?

Patient being treated for MDR-TB in a Russian prison

Patient being treated for MDR-TB in a Russian prison

In May 2016 a major change took place in the recommended treatment for drug resistant TB. Previously treatment for drug resistant TB had often required a large number of drugs being taken for up to two years. Also the drugs often caused severe side effects in patients. So various efforts were being made to develop shorter regimens which were easier to take.

The first shorter and easier to tolerate regimen is known as the Bangladesh regimen. It appears to have a higher cure rate than “standard” MDR-TB regimens. In May 2016 the World Health Organisation recommended that there should be a major change to the treatment for drug resistant TB with shorter regimens being made available for many patients. There is more about the treatment of drug resistant TB.

Treatment outcomes

Only 52% of the MDR-TB or RR-TB patients who started treatment in 2013 were successfully treated. 17% of the patients died and in 9% of the patients their treatment failed. 22% were lost to follow up or not evaluated.

MDR-TB high burden countries

There are 30 “high burden” countries for MDR-TB. The list of high burden MDR-TB countries was revised in 2016.

The tables below show the estimated number of cases for each “high burden” country. But these are only the estimates for the number of cases of MDR-TB among those cases of pulmonary TB notified to WHO. There will in addition have been many cases of MDR-TB among those cases of TB which were either not detected and/or not notified.

Statistics for MDR-TB in “High Burden” Countries
Country Estimated % of new cases with MDR-TB or RR-TB Estimated % of previously treated cases with MDR-TB or RR-TB Incidence of MDR-TB or RR-TB % of MDR among MDR-TB or RR-TB cases
Angola 2.8 21 4,100 66
Azerbaijan 13 29 2,500 96
Bangladesh 1.6 29 9,700 93
Belarus 37 69 3,500 97
China 6.6 30 70,000 86
DPR Korea 2.2 16 6,000 90
DR Congo 3.2 14 10,000 67
Ethiopia 2.7 14 6,200 63
India 2.5 16 130,000 92
Indonesia 2.8 16 32,000 69
Kazakhstan 25 43 8,800 92
Kenya 1.3 9.4 2,000 50
Kyrgyzstan 32 56 5,000 92
Mozambique 3.7 20 7,300 86
Myanmar 5.1 27 14,000 93
Nigeria 4.3 25 29,000 66
Pakistan 4.2 16 26,000 77
Papua New Guinea 3.4 26 1,900 38
Peru 5.9 21 3,200 91
Philippines 2.6 29 17,000 76
Republic of Moldova 32 69 3,900 79
Russian Federation 22 53 60,000 90
Somalia 8.7 47 3,100 65
South Africa 3.5 7.1 20,000 60
Tajikistan 14 77 1,900 51
Thailand 2.2 24 4,500 87
Ukraine 25 58 22,000 95
Uzbekistan 24 63 10,000 97
Viet Nam 4.1 25 7,300 67
Zimbabwe 3.2 14 1,800 67

You can read more about:

Drug resistant TB

Drug resistant TB in South Africa


Major Sources for MDR-TB

WHO treatment guidelines for drug resistant tuberculosis 2016 update  http://apps.who.int/iris/handle/10665/250125/

Global Tuberculosis Control 2016, WHO, Geneva, 2016 www.who.int/tb/publications/global_report/en/

Multidrug-resistant Tuberculosis (MDR-TB) 2016 update, WHO, Geneva, 2016 www.who.int/tb/publications/factsheets/en/