MDR and XDR TB: Causes & Cure

What is MDR TB?

Tuberculosis is caused by bacteria that have multiple strains in seven groups or categories. Over the years the bacteria has evolved to become resistant to the most commonly used medicines and they are able to pass this resistance ability to their descendents thus creating a more serious form of the disease.

WHO Recommended Treatment for TB

WHO mandates that patients having TB must be given a combination of four antibiotics for two months. These first-line drugs include:

?     Rifampicin

?     Isoniazid

?     Ethambutol

?     Pyrazinamide

This treatment must be followed by a four-month course of two antibiotics such as:

?     Isoniazid

?     Rifampicin

Failure to follow this regimen is one of the crucial factors that can lead to the bacteria developing resistance.


Causes of MDR TB

There are several reasons why the bacteria have become so resilient. They are:

?     The drug resistant strains are passed on from the patients to the people around them because of the unsanitary conditions in which they live. Ideally, TB patients must be quarantined for as long as they are contagious.

?     When a patient develops TB, it is very essential that the complete course of the treatment should be followed and completed. When the patient stops treatment before 6 months or the prescribed time, the remaining bacteria in the body become immune to the antibiotic. Even if the patient were to restart the treatment, the same medication will not go any good.

?     The patient receives the wrong combinations of the medicines for his/her specific strain of TB.

?     The patient is not monitored properly.

?     The quality of medicines is substandard.

?     The dosage is administered incorrectly.

?     The medicines are not stored properly, because of which they lose their effectiveness.


Reasons Why MDR TB is Spreading Fast

It is becoming very difficult to control TB in countries like India. This is because the treatment for the MDR TB can now take up to 2 years to complete and patients need to take second-line drugs by way of injections that must be given every day. Other factors are:

?     Unavailability of the advanced molecular based testing to detect MDR strains such as Xpert MTB/RIF

?     The costs of the tests for MDR TB

?     The costs of medicines to treat MDR TB

?     Unavailability of the specific medicines needed to treat MDR TB

?     Side effects of the most commonly used medicines (Some of them are toxic and can damage the liver)



XDR TB is the short form of Extensively Drug Resistant or Extremely Drug Resistant TB. This is a more advanced form of MDR TB and is extremely difficult to diagnose because most conventional laboratories do not have the necessary equipment needed to detect it. This strain of the disease is also almost impossible to treat because it is resistant to most of the second-line drugs that are given to control it such as:

?     Fluoroquinolones

?     Amikacin, capreomycin, and kanamycin, each administered by way of injections

?     Isoniazid and rifampin (first-line drugs)


Cures for XDR TB

In recent times, certain medicines have been found to be effective in treating XDR TB. They are given in combinations of:

?     Broad-spectrum antibiotic meropenem–clavulanate

?     Antileprosy medications linezolid and clofazamine

?     Bedaquiline manufactured by Johnson & Johnson’s

Like drugs for MDR TB, they are to be given for 2 years. However, these medications have only a 50% success rate and this success also depends on various factors like the level of resistance the patient has developed and how early the treatment was started.


Side Effects for Second-line Drugs

The medicines given for both MDR TB and XDR TB are highly toxic. While patients might need radical lung surgery, they can also have side effects like:

?     Nausea

?     Hearing problems, sometimes complete failure

?     Pain in the joints

?     Severe depression with suicidal tendencies



TDR TB is the newest version of the disease that is coming forward. This term stands for Totally Drug Resistant TB or a form of TB that cannot be controlled by any of the anti TB medicines that we know of today. Although these reports have not been proved conclusively and tests are still being conducted to prove its existence, the initial findings are alarming.


Tuberculosis is a serious disease that is afflicting millions of people all over the world. Taking precautions and maintaining a sanitary environment cannot be stressed enough. Please do remember that this article is only intended to offer basic information and does not in any way claim to be an authority on the disease. Please contact a certified medical practitioner for more detailed information.

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