As TB Rates Go Down, Drug Resistance Causes Worry

Even as TB rates decline in the United States, the worry is that cuts to labor-intensive control programs will fuel longer-term problems such as drug-resistant strains, researchers said ahead of Tuesday's World TB Day. In California, the proportion of multidrug-resistant TB (MDR-TB) cases that were one drug away from being extensively drug-resistant (XDR-TB) grew from 7 percent in 1993 to 33 percent in 2006.

California's immigrant communities are especially vulnerable, since many immigrants are born in or travel to countries where TB is endemic, including Mexico, China, and India. Among the state's 451 drug-resistant TB cases during 1993-2007, about 83 percent involved foreign-born persons.

San Francisco, where about one-third of residents are foreign-born, has the nation's highest TB rate. The city adopted a more hands-on approach to ensuring treatment adherence after a spike in TB in the 1990s. However, since 1996 city TB control workers have been cut by more than half, said Masae Kawamura, San Francisco Department of Public Health's (DPH) director of TB control. About 85 percent of the city's 609 drug-resistant TB cases logged between 1993 and 2006 were found in foreign-born persons, as were 83 percent of its 18 XDR-TB cases. That is "just the tip of the iceberg," Kawamura said.

San Francisco patients visit DPH's TB clinic for their daily treatment. Field staff members go out to patients who, for work, illness, and other reasons, cannot come to DPH for directly observed treatment.

The city's budget cuts have hurt its ability to proactively screen for TB in high-risk areas and treat latent cases, said Jennifer Grinsdale, a program manager and epidemiologist with DPH's TB control program. "Anywhere from two to 10 years from now, we'll see the impact for this," she predicted.

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