Resistant Strains

© Jean-Marc Giboux

“Using the current TB tools to cope with DR-TB is like trying to put out a forest fire with a garden hose.”  Françoise Louis, MSF TB Advisor.

MSF encountered cases of drug-resistant tuberculosis (TB) in the former Soviet Union in the 1990s. The TB mycobacterium had mutated into a form that was resistant to some of the drugs used in standard TB treatment.
 
More and more people are contracting these drug-resistant forms either as a result of treatment failure or by coming directly into contact with the resistant form of the TB bacteria.  

A significant number of others go undiagnosed because the diagnostic tests that exist don’t work adequately, or are difficult to use and not adapted for remote settings.

TB opens up new, more deadly front in people living with HIV
Because of the difficulties in diagnosing drug resistant TB in remote settings,  it is hard to get accurate information on just how far these resistant strains have spread. What is alarmingly clear is that rate of drug-resistant strains is rising rapidly among people living with HIV/AIDS, particulary in Southern Africa.

Read more

Co-Infection with HIV

HIV TB: The Failure to Act

 

Defining drug-resistant TB

A patient is defined as suffering from multidrug-resistant TB (MDR-TB) when they are resistant to at least rifampicin and isoniazid, the two most powerful first-line TB drugs.

Extensively drug-resistant TB (XDR-TB) has been recently defined as a form of TB resistant to at least the two first-line drugs rifampicin and isoniazid and additionally to a fluoroquinolone and one of the injectable drugs (kanamycin, amikacin or capreomycin) among the second-line drugs.

 

XDR-TB: Virtually no options
In 2006, the world received a dramatic wake-up call about the dangers of drug-resistant TB in places where HIV is present. In the KwaZulu Natal province of South Africa, a group of people were identified as having an extensively resistant strain of TB that responded to nearly none of the known TB treatments.

52 out of the 53 people infected with this more deadly strain died within a space of a couple of weeks even before their diagnosis was confirmed. 

In fact MSF had already been treating patients with extensively drug resistant TB (XDR) in Eastern Europe for several years.  The alarming fact was the rapid spread of this drug-resistant strain to countries with high HIV prevalence which lead therefore to even higher death rates.

44 of those tested were HIV positive. The combination of XDR-TB and HIV infection is particularly dangerous because due to the difficulties of diagnosing TB in HIV patients, diagnosis is often delayed to a point where the patient is too sick to respond to treatment.

Up to now, XDR-TB cases have been identified in more than 40 countries.

Inadequate tools to tackle the challenge of DR-TB
Diagnosing and treating patients with drug-resistant TB presents enormous challenges - particularly in the remote settings where MSF works.
 
The diagnostic tools available take much longer to produce results than for standard TB diagnosis because in addition to seeing whether someone is infected you have to find out which drugs work and which don’t. They’re also very complex, and so cannot be carried out in those under-resourced areas where we work: that means that for many patients with drug resistant TB, the results often come too late and the patient dies before they are correctly diagnosed.  
 
Treatment for drug-resistant strains of TB rely on older, less-potent drugs that may trigger severely toxic side effects. In MSF projects in Eastern Europe, The Caucasus and Central Asia, most patients are hospitalised and isolated for the initial “intensive” stage of their treatment whilst they are still infectious. This period can last up to four months. Cure rates are dramatically lower than for standard TB treatment: 60% in the case of MDR. In the case of XDR-TB, the options for successful treatment are virtually non-existent.

© Donald Weber/Atlas Press

"I get terrible headaches, dizziness...it is better now, but there were times in the past when I just wanted to die. Maybe it was the drugs, or maybe the length of the treament, but it all just seemed too much" Sarsenbai Menglibaev, a patient from the Nukus MSF project in Uzbekistan, with his family.

Sarsenbai's story

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TB Fact Sheet

MSF and Tuberculosis

Diagnosing Tuberculosis

Treating Tuberculosis

Co-infection with HIV

Looking for New Tools