Drug resistant Tuberculosis (TB)

Tuberculosis, MTB, or TB (short for tubercle bacillus) is a common, and in many cases lethal, infectious disease caused by various strains of mycobacteria, usually Mycobacterium tuberculosis.

Tuberculosis typically attacks the lungs, but can also affect other parts of the body. 

It is spread through the air when people who have an active TB infection cough, sneeze, or otherwise transmit respiratory fluids through the air.
Tuberculosis or TB remains a significant health problem in Asia and Africa causing extensive human suffering and loss of life. In recent years the causative bacteria has become resistant to available anti-TB drugs. 
The resistance can be of various levels, such as MDR or multi-drug resistant TB, when the most commonly used drugs rifampicin and isoniazid become ineffective. 
It becomes difficult to treat XDR or extensively drug resistant TB where the bacteria become resistant not only to these two drugs but also injectable and other second-line drugs.
According to the World Health Organisation’s Global TB report 2012, India, China, Russia and South Africa have almost 60% of the world’s MDR-TB burden.
There are multiple causes of drug resistance TB.

• poor management of TB treatment which includes inconsistent or partial treatment, 
• prescription of incorrect treatment regimens or an unreliable or erratic supply of drugs. ,
• The use of spurious serology based diagnostic tests leading to inaccurate diagnosis is also an important contributing factor.

In recent years, the government has made a conscious effort to scale up DOTS Plus services i.e. a specialized strategy that focuses on drug resistant TB and is now available across 35 States in India. Introduction of newer diagnostic tests such as Xpert MTB/RIF which can detect MDR-TB from the sample as well as resistance to rifampicin, a surrogate marker for MDR-TB, in less than two hours has become important to rapidly diagnose MDR-TB.