More Cases of Drug-Resistant Tuberculosis Complicate Care but Spur Global Research and Innovation

For most Americans, neither tuberculosis treatment nor prevention is a concern or a priority. Effective tuberculosis care has made this dangerous disease quite rare in the United States. In 2006, just 13 767 cases were reported (4.6 cases per 100 000 population), 56.7% of which were among foreign-born persons (1).

But for many people elsewhere in the world, tuberculosis is a constant threat. The disease, with its symptomatic coughing, weight loss, fatigue, fever, and pleurisy, is a leading cause of mortality. It results in approximately 1.7 million deaths annually, according to the World Health Organization (WHO). Most of these deaths occur in developing nations and are due to the lack of access to effective treatment for drug-susceptible tuberculosis.

Emerging data indicate that multidrug-resistant tuberculosis (MDR-TB), which is resistant to at least isoniazid and rifampin, is playing a growing role in morbidity and death. Among 9 million annual new cases of tuberculosis, an estimated 490 000 are MDR-TB, according to WHO. Approximately one quarter of these cases are fatal. Since the 2006 international recognition of extensive drug-resistant tuberculosis (XDR-TB)—MDR-TB that is also resistant to 3 or more of the 6 classes of second-line drugs—has heightened global concerns about the future of tuberculosis. Although the number of XDR-TB cases remains small, at an estimated 40 000 new cases per year, approximately half of these cases are fatal.

Drug-resistant strains of Mycobacterium tuberculosis have made tuberculosis prevention, diagnosis, and treatment more difficult, more complicated, and more expensive. “To say that an increase in MDR-TB and XDR-TB would undo all of the good work of the past 10 years is simply not true, but it would significantly impede progress,” said Paul Nunn, MD, coordinator in the WHO's Stop TB Department.

Drug-resistant strains have also drawn attention to deficient progress in diagnostic tools and treatments for …