Understanding in a NEW mode of MDR TB

Multidrug-resistance tuberculosis (MDR TB), a known form of tuberculosis that is resistant to one or multiple primary drugs (isoniazid and rifampin) used normally in the treatment of tuberculosis.

Extensively drug resistant TB (XDR TB) is resistant to at least isoniazid and rifampin among first line of anti-TB drugs and is resistant to any anti-fluroquinolone and at least one of the three second line injectable drugs. When bacteria develops its ability to withstand the antibiotic attack, lead to the development of resistance to one or several forms of treatment and this ability relays it to the offspring. Due to this inheritance of the bacteria, the effect of resistance bacteria spreads from one person to another. However, it is of obvious reasons that inadequate treatment and improper use of the ant-TB drugs remain the main reasons of drug resistance TB.

The improper treatment remains the star mark for MDR TB development. Some physicians does not prescribe proper treatment regimens or also when patient does not properly adhere to the treatment. Improper treatment leads these bacilli to develop natural resistance over the drug and transmit this to inheritance. Eventually majority bacilli become resistant in the body. Once a strain of MDR TB develops it can be transmitted to others.

MDR TB has been a major concern in HIV-infected persons. Some of the major factors include:

  • Delayed diagnosis and delayed determination of drug susceptibility.
  • Susceptibility of immunocompromised individuals for not only acquiring MDR TB but also for the rapid disease progression. In turn leading to transmission to other immunosupressed patients.
  • Inadequate isolation procedure and other environmental safety concerns, like in remote areas or in confined areas (prison).
  • Noncompliance or intermittent compliance with anti-tuberculosis drug therapy.

New quest in TB:

Tuberculosis causing germ likely to have grown in ancient man when he started to live in larger communities. It probably early humans out of Africa at least 70,000 years ago. While communicating this study, it has been identified that 39 new genes drives this dangerous drug resistant TB [Read More: www.channelnewsasia.com/news/health/new-genes-found-in-drug/798784.html]. A report published in the Asian Scientist, 8th August 2013 based on a new promising drug discovery for MDR TB by South Korian and Singapore Researchers, and the drug was successfully tested on mice. The research was published in the journal Nature Medicine where this drug inhibits the growth of M. tuberculosis through a novel mechanism rather than the known previous drugs [Read More www.asianscientist.com/in-the-lab/multidrug-resistant-tuberculosis-drug-developed-2013/]. Although it is new to understand the multiple ways to inhibit MDR TB, and step wise multiple mutation would be one of the major cause of M. tuberculosis to be drug resistant and is proved in a research published in a journal Nature Genetics [Read More: www.sciencedaily.com/releases/2013/09/130901153345.htm].

The success of treatment lies in how quickly the case of TB is been identified. Tests to determine resistance to various drugs take several weeks, hence an effective drug regimen must be identified. There are multiple strains of MDR TB which are resistant to seven or more drugs, making the identification of proper drug to be difficult. The better way to deal with this problem is to recommend the newly discovered cases of TB in populations at high risk for MDR TB to be treated with four drugs rather than the standard three as part of the initial treatment.

 

Sources:

  1. Centers for Disease Control and Prevention. [http://www.cdc.gov/tb/statistics/reports/2011/default.htm]
  2. American Thoracic Society, Centers for Disease Control and Prevention and Infectious Disease Society of America.
  3. World Health Organization, Global Tuberculosis Control Report, 2012.
  4. Asian Scientist, Channel New Asia, Science Daily

Suggested Reading:

  1. www.ncbi.nlm.nih.gov/pmc/articles/PMC1281517/
  2. www.the-scientist.com/?articles.view/articleNo/37324/title/Decoding-Drug-Resistant-TB/
  3. www.cdc.gov/tb/publications/factsheets/drtb/mdrtb.htm
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About Saumyadip

Science Communicator and Biologist. Keep interests in host-pathogen interaction research. Specifically bacterial infection mechanism, host infection evasion and immune susceptibility of host. Working as Senior Research Fellow at Thrombosis Research Institute, Bangalore.
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