Multidrug-Resistant Tuberculosis

DURING THE PAST DECADE MULTIDRUG-RESISTANT TUberculosis (MDR-TB) defined as resistance to at least isoniazid and rifampin has declined in the United States. The number of reported MDR-TB cases has decreased from 486 in 1993 to 114 in 2003 and the proportion of resistant strains of Mycobacterium tuberculosis has decreased by half. The decline is heartening but this issue of JAMA includes 2 reports from California and Russia showing why celebration would be premature. In this issue of JAMA Granich and colleagues show that California has not shared in the proportionate decline of resistant strains. From 1994 to 2003 the authors analyzed the sensitivity of 28 712 culture-positive cases of TB and identified 407 MDR-TB cases. Although the absolute number of MDR-TB cases per year decreased during the 10-year period the number of sensitive cases also declined leading to stable proportions of resistance. Matching several databases they identified key risk factors for resistance including a previous diagnosis of TB a positive smear Asian/ Pacific Islander ethnicity and being a US resident for less than 5 years. In fact 84% of cases were in foreign-born persons residing in the United States. The authors conclude that much of the MDR-TB problem in California was imported underscoring the global nature of TB. (excerpt)