Drug-Resistant TB Spreading Around the World

Extensively drug-resistant TB (XDR-TB), first reported by CDC and the World Health Organization in March 2006, is continuing to spread. While multi-drug-resistant TB (MDR-TB) is immune to the most powerful first-line TB treatments, XDR-TB is also resistant to some second-line TB drugs, making it very difficult to treat. Health advocates say new treatments are needed.

Last August, all but one of 53 XDR-TB-infected patients in one South African province died from the disease; most were HIV co-infected. Now, the country has an estimated 600 XDR-TB cases, reaching all provinces, Karin Weyer of the South Africa Medical Research Council told last week's 14th Conference on Retroviruses and Opportunistic Infections. Among that estimated number of cases, the mortality rate is 84 percent. More than 80 percent are HIV co-infected.

Regular TB can be treated by a six-month course of antibiotics. When TB drugs are given inappropriately, or patients do not adhere to treatment, MDR-TB can arise, requiring treatment for 18 months or two years. Given enough opportunity, XDR-TB can emerge.

The Global Alliance for TB Drug Development is working with drug firms, academic institutions, and researchers to find new TB drugs, said Maria Freire, the alliance's CEO. There are some promising developments, she said, but the development of an ideal candidate -- one that would attack TB in ways that circumvent drug resistance; could be taken with antiretrovirals; and would be effective within two months or less -- is likely a decade or more away.

Back to other news for March 6, 2007