Doctors from the National Hospital In Mumbai reported the existence of a new strain of mycobacterium causing tuberculosis which is resistant to all drugs that are presently used in the therapy of the disease. The strain has been called TDR TB (totally drug-resistant tuberculosis). Until the first half of January 2012, 12 cases of infection caused by the new strain were confirmed and 3 of those patients died because of it.
Most probably those patients were not initially infected with TDR TB, but the bacteria mutated as result of inadequate therapy (i.e. improper drugs, too short duration of therapy). However, there is no evidence that the new strain is less infectious or its transmission is less efficient.
Since the 1960’s the most common method of tuberculosis treatment was to administer a combination of antibiotics, among others isoniazid and rifampicin. Treatment lasted for many weeks. However, since the beginning of the 1990’s growing resistance of mycobactieria to the used drugs has been observed. In the year 1992 MDR TB (Multi drug-resistant tuberculosis) was discovered and then in the year 2006 a strain called XDR TB (extensively drug-resistant tuberculosis) was identified. The latter caused 25000 infections in 58 countries annually.
India is not the first country where infections with totally drug-resistant tuberculosis occurred. TDR TB strains caused infections in Italy in 2007 and Iran in 2009. Data about these cases is rather scarce. According to Giovanni Migliori, director of Centre for Tuberculosis and Lung Diseases in Tradat, TDR TB is a new form of XDR TB. This is confirmed by epidemiologist Carole Mirnick from Harvard Medical School in Boston. She also says that if infections caused by a certain pathogen are invariably treated with the same drugs for several decades, emergence of resistant strains is inevitable. Although tuberculosis is after AIDS the second most deadly infectious disease world-wide. There were no research on new methods of treatment for many years. Currently, scientists are trying to reduce the duration of the treatment from 6 to 4 months by using moxifloxacin.
The hope for treatment of resistant strains is to administer new combination of medicines. Research shows that combination of two substances: pyrazinamide and moxifloxacin in 2 weeks time may eliminate considerable number of bacillus from the organism. Research also concerns the influence of bedaquiline on the disease. However, recently published results pertain only to strains from Africa.
WHO and Indian authorities do not believe that the germs that cause the infections are resistant to all available drugs. According to World Health Organization, the infections in India were caused by XDR TB. Also, WHO says that there is not enough data to confirm the existence of TDR TB and it does not recognize the name. Maybe the research on the recent cases in India will provide greater insight into the matter.
Written by: Adam Lebiediew, Jerzy Bednarski, Maciej Jakuszko, Michał Hys
Would You like to know more? Watch on MEDtube.net: Laryngeal Tuberculosis – Endoscopic View