An estimated one third of the world's population is infected with Mycobacterium tuberculosis, and nearly 9 million persons develop disease caused by M.
tuberculosis each year. Although
tuberculosis (TB) occurs predominantly in resource-limited countries, it also occurs in the United States. During 1985-1992, the United States was confronted with an unprecedented TB resurgence. This resurgence was accompanied by a rise in multidrug-resistant TB (MDR TB), which is defined as TB that is resistant to the two most effective first-line therapeutic drugs,
isoniazid and
rifampin. In addition, virtually untreatable strains of M.
tuberculosis are emerging globally. Extensively
drug-resistant (
XDR) TB is defined as MDR TB that also is resistant to the most effective second-line therapeutic drugs used commonly to treat MDR TB:
fluoroquinolones and at least one of three
injectable second-line drugs used to treat TB (
amikacin,
kanamycin, or
capreomycin).
XDR TB has been identified in all regions of the world, including the United States. In the United States, the cost of hospitalization for one
XDR TB patient is estimated to average $483,000, approximately twice the cost for MDR TB patients. Because of the limited responsiveness of
XDR TB to available
antibiotics, mortality rates among patients with
XDR TB are similar to those of TB patients in the preantibiotic era. In January 1992, CDC convened a Federal TB Task Force to draft an action plan to improve prevention and control of
drug-resistant TB in the United States (CDC. National action plan to combat
multidrug-resistant tuberculosis. MMWR 1992;41([No. RR-11]). In November 2006, CDC reconvened the Task Force to draft an updated action plan to address the issue of MDR TB and
XDR TB. Task Force members were divided into nine response areas and charged with articulating the most pressing problems, identifying barriers to improvement, and recommending specific action steps to improve prevention and control of
XDR TB within their respective areas. Although the first priority of the Federal TB Task Force convened in 2006 was to delineate objectives and action steps to address MDR TB and
XDR TB domestically, members recognized the necessity for TB experts in the United States to work with the international community to help strengthen TB control efforts globally. TB represents a substantial public health problem in low- and middle-income countries, many of which might benefit from assistance by the United States. In addition, the global TB epidemic directly affects the United States because the majority of all cases of TB and 80% of cases of MDR TB reported in the United States occur among foreign-born persons. For these reasons, the Action Plan also outlines potential steps that U.S. government agencies can take to help solve global
XDR TB problems. Unless the fundamental causes of MDR TB and
XDR TB are addressed in the United States and internationally, the United States is likely to experience a growing number of cases of MDR TB and
XDR TB that will be difficult, if not impossible, to treat or prevent. The recommendations provided in this report include specific action steps and new activities that will require additional funding and a renewed commitment by government and nongovernment organizations involved in domestic and international TB control efforts to be implemented effectively. The Federal TB Task Force will coordinate activities of various federal agencies and partner with state and local health departments, nonprofit and TB advocacy organizations in implementing this plan to control and prevent
XDR TB in the United States and to contribute to global efforts in the fight against this emerging public health crisis.