From mono, multiple to extensive drug resistant TB: Where are we heading for?

Background: A short course of antitubercular drugs in 1960s offered the prospect of eradicating this disease. By late 1980s HIV pandemic lead to a rapid upsurge of tuberculosis (TB) and shattered this hope. In the 1990s, multidrug-resistant (MDR) tuberculosis received widespread attention and in this present decade, we are heading towards an emergence of extensively drug-resistant (XDR) TB and adding a new chapter to the history of this disease. Methods: The emergence of XDR-TB, spread and the reasons for its emergence was studied from the available and published literature from January 1996 till December 2006. Search strategy involved primary, secondary literatures with search term: XDR-TB, spread of XDR-TB. Official websites of WHO and Global TB Alliance were also accessed for latest updates. Data extraction was independently done by the authors. Available relevant information was pooled and arranged with respect to XDR-TB emergence, reasons, clinical studies and preventive measures. Current status on anti-TB drug research was also looked into. Results: A total of 14 articles were obtained. However, these were clinical studies from single or multicenters highlighting the incidence of XDR-TB. Information on reasons for drug resistance, preventive measures, status in developing countries were obtained from WHO website. Global TB Alliance mentioned only 3 compounds under clinical testing against TB. Major causes for XDR-TB emergence included an incorrect prescription of drug regimens, poor drug quality, erratic drug supply, non-adherence by patients and poor infection control. Conclusion: XDR-TB has emerged due to negligent case-management and poorly functioning public-health services. An acquisition and transmission of drug-resistant strains add to their incidence. However till date the overall incidence is arguably infrequent. The real problem from a public-health perspective therefore is to prevent transmission of resistant strains. The need of the hour is to gear up a sound public-health practice. Major attention to issues like research in developing safe and effective newer anti-TB compounds, which should be made available at an economical rate, is what we recommend. © 2007 - IOS Press and the authors. All rights reserved.