DOTS Programme, MDR-TB and XDR-TB

DOTS, is an acronym for Directly Observed Treatment, Short course. The DOTS strategy represents the most important public health breakthrough of the decade, in terms of lives which will be saved. It is based largely on research done in India in the field of TB over the past 35 years. As it is the only strategy effective in controlling TB on a mass basis, nearly 100 countries are following it.

DOTS has five components:

• Government commitment (including both political will at all levels, and establishing a centralized and prioritized system of TB monitoring, recording and training)
• Case detection by sputum smear microscopy
• Standardized treatment regimen directly observed by a healthcare worker or community health worker for at least the first two months
• A regular drug supply
• A standardized recording and reporting system that allows assessment of treatment results

Other Notes

• The technical strategy for DOTS was developed by Dr. Karel Styblo in the 1980s primarily in Tanzania.
• In 1989, the World Health Organization and the World Bank began investigating the potential expansion of this strategy. In July 1990, the World Bank, under Richard Bumgarner’s direction, invited Dr. Styblo and WHO to design a TB control project for China. By the end of 1991, this pilot project was achieving phenomenal results, more than doubling cure rates among TB patients. China soon extended this project to cover half the country.
• In India, Government had adopted the revised strategy for TB in the form of DOTS.
• Since 1993, DOTS has been pilot tested in 20 sites in India as RNTCP.
• In RNTCP the proportion of TB cases confirmed in the laboratory is double that of the previous programme, and the cure rate is nearly triple that of the previous programme. The operational feasibility of DOTS in the Indian context has been demonstrated, with 8 out of 10 patients treated in the programme being cured as compared to three out of 10 under the previous regime.

DOTS has also been shown to prevent the emergence of multi-drug resistant tuberculosis (MDRTB) and to reverse the trend of MDRTB in communities in which it has emerged. Also DOTS can cure TB even in HIV-positive patients. Entire country has been covered under DOTS Strategy by March 2006. The international Joint Monitoring Mission (JMM) in October 2006, has hailed it as the fastest expansion of DOTS in the world.

Isoniazid

Isoniazid / Laniazid or Nydrazid) is the classic antituberculosis medication, first discovered in 1912. It was found to be effective against tuberculosis in 1950s. However, Isoniazid is never used on its own to treat active tuberculosis because resistance quickly develops.

Rifampicin

Rifampicin is a bacteriocidal antibiotic drug. It has been used for TB along with isoniazid, ethambutol, pyrazinamide and streptomycin etc.

MDR-TB

TB that is resistant at least to isoniazid and rifampicin the two most powerful first-line anti-TB drugs is called the Multi-drug-resistant tuberculosis (MDR-TB). It develops because the when the course of antibiotics is interrupted and the levels of drug in the body are insufficient to kill 100% of bacteria. This means that even if the patient forgets to take medicine, there are chances of developing MDR-TB.

MDR-TB is treated with secondline of antituberculosis drugs such as a combination of several medicines called SHREZ
^{(Streptomycin+isonicotinyl Hydrazine+Rifampicin+Ethambutol+pyraZinamide)+MXF+cycloserine.}

XDR-TB

When the rate of multidrug resistance in a particular area becomes very high, the control of tuberculosis becomes very difficult. This gives rise to a more serious problem of extensively drug-resistant tuberculosis (XDR-TB). XDR-TB is caused by strains of the disease resistant to both first- and second-line antibiotics. This confirms the urgent need to strengthen TB control.

Thus, Extensively-drug resistant TB (XDR-TB) is a sub-set of MDR-TB which is further resistant to at least two more drugs which are second line drugs and is thus virtually incurable. XDR TB was first described in March 2006 following a joint survey of laboratories by the WHO, IUATLD, and CDC, Atlanta.