Study Shows Declining Number of Cases of XDR-TB

CHICAGO – A new report suggests that the number of cases of extensively drug-resistant tuberculosis (XDR-TB) in the U.S. has declined in the past 15 years, but new cases continue to be reported, according to the study published in the Nov. 12 issue of JAMA. The researchers note the decrease in the number of XDR-TB cases coincides with improved TB and HIV/AIDS control.  

“Tuberculosis remains the leading cause of infectious disease death among adults worldwide,” the authors provide as background information. “In recent years, drug-resistant TB has emerged as an expanding threat, with an estimated 489,000 new cases in 2006. Treatment of multidrug-resistant TB (MDR-TB) is more than 100 times as costly as treatment of drug-susceptible TB, requiring intensive case management for its prolonged (18-24 months) and more toxic treatment course.”  Treatment success rates are lower for patients with MDR-TB as compared to those with drug-susceptible TB. In 2005, a new category of TB disease was defined --  extensively drug-resistant TB (XDR-TB) – because TB cases with even great drug resistance had emerged, especially in settings of high human immunodeficiency virus (HIV) prevalence throughout the world.