Multidrug-resistant Tuberculosis (MDR-TB) and Extensively Drug-Resistant Tuberculosis

Tuberculosis (TB) is an infectious disease caused by a germ called Mycobacterium tuberculosis.Tuberculosis is spread through the air when a person sneezes, coughs or breathes.

Tuberculosis primarily attacks the respiratory system although it can attack other organs as well.The symptoms of tuberculosis include fever, night sweats, weight loss, chest pain and coughing.

Tuberculosis can become resistant if a patient is not treated properly or does not take prescribed medications or in case does not receive the right drug.

The emergence and spread of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) are a major medical and public problem, threatening a global health.

Multidrug-resistant tuberculosis is resistant to at least two of the main drugs used to treat tuberculosis-isoniazid (INH) and rifampicin.

MDR-TB is become a challenge to treat a tuberculosis due to its complex diagnostic nature and treatment requirements. MDR-TB develops as otherwise treatable tuberculosis when the course of antibiotics is interrupted and the level of the drug in the body are insufficient to kill 100% of bacteria.

About 440,000 new cases of MDR-TB are identified every year, resulting in about 150,000 deaths.

In addition to the increased difficulty in treating the disease, the patient remains infectious longer increasing the risk to the public and to healthcare workers.

MDR-TB also appears in association with HIV infection and AIDS, further compromising the health and the immune system of these patients. HIV itself does not increase the chance of drug resistance. HIV does accelerate the progression of tuberculosis infection into active tuberculosis disease.

MDR-TB can cause death within a few weeks in persons with HIV/AIDS.

XDR-TB is a form of tuberculosis caused by bacteria resistant to anti-tuberculosis drug. XDR-TB arises as a mismanagement of drugs by individual with multidrug resistant TB (MDR-TB).

XDR-TB is defined as a tuberculosis that has developed a resistant to at least rifampicin, isoniazid as well as any member of quinolone family and at least one of the second-line anti tuberculosis injectable drugs kanamycin, capreomycin or amikacin (WHO, 2006).

One in three people in the world is infected with TB bacteria (WHO, 2007). XDR-TB raises a concern of tuberculosis endemic with restricted treatment options.

XDR-TB ratio is unknown as many countries lack proper equipments to diagnose the disease. It is estimated that there are increase in 40,000 new cases around the globe every year.

XDR-TB also spread through the air, when a person with infectious tuberculosis coughs, sneezes, talks or spits they release tuberculosis germs. A person needs only a small number of these to get infected. The number of tuberculosis bacteria depends on a factor such as number and concentration of infectious people in any one place. The disease is spread easily on places where a high concentration of tuberculosis bacteria occurs such as in overcrowded houses, hospitals or prisons.

Treatment for XDR-TB and MDR-TB are the same. Treatment of both these types of tuberculosis requires extensive chemotherapy for nearly two years. Second-line drugs are highly toxic than standard anti tuberculosis drugs and responsible for large number of side-effects including hepatitis, depression and hallucinations. Patients are hospitalized for long periods in isolation.

XDR-TB and MDR-TB is found more common in people who:

1. Do not take  tuberculosis  medicine regularly.

2. Do not take the combination of  tuberculosis drugs as prescribed by doctor.

3. Develop  tuberculosis again, having history of  tuberculosis .

4. People living in areas around the world where drug-resistant  tuberculosis is common. 

MDR-TB and XDR-TB is rare, however minimum of 1 case is found in 77 countries. Information from reliable data shows that 9% of MDR-TB cases have XDR-TB throughout the globe.

According to WHO data, estimates about 650,000 MDR-TB cases in the world at any one time. Only a fraction of these cases are detected and treated properly.

To avoid MDR-TB and XDR-TB similar ways are used as those for prevention of ordinary tuberculosis.

1. Avoid close contact with patient having tuberculosis.

2.  Use surgical masks during visit to patients.

3.  Effectiveness of ventilation.

References:

World Health Organization (2006), “Frequently asked question-XDR-TB”.

World Health Organization (2007), “Fact Sheet No. 104: Tuberculosis.

http://www.who.int/tb/challenges/en/

For quite some time I have been thinking of global health issues as they concern all of us, in particular the developing world.

I am excited to write this first post in my new blog 'Health Frontiers'. I hope to cover in this blog issues of health in global perspective. The main focus will be the problems of the third world countries which are very unique because these countries are recognized to have double burden of conventional diseases as well as non-communicable diseases (NCDs) which are now a development concern. 

Health is a fast advancing field. What is very important in particular is the scientific advancements on daily basis. Every day some where the world some useful and interesting development is made. I hope to cover such scientific developments be it from medicine, policy or from system angles.