As TB rates go down, drug resistance in California's immigrant communities causes worry
By Juliana Barbassa




Posted: 03/22/2009 09:31:15 PM PDT


Even as tuberculosis rates decline in the United States, drug-resistant strains of the disease showing up in California's large immigrant population are becoming increasingly hard to treat.

Researchers are concerned about this trend while funding for labor-intensive disease control programs is being cut in cities such as San Francisco, which has the highest TB rates in the country.

Drug resistance develops when patients start feeling better and interrupt their treatment, giving bacteria an opportunity to develop a defense against the medication.

The picture is grim, and World TB Day on Tuesday is an attempt to raise awareness of a disease that infects about 9 million people, particularly in Asia and Africa. About 5 percent of those patients are immune to the best drugs. About 2 million die annually.

Immigrant communities in states such as California are particularly vulnerable because many people are foreign born or travel frequently to countries where TB is a greater risk, including Mexico, India and China.

The state leads the nation with 2,696 TB recorded cases in 2008 — and with 451 cases of drug-resistant TB identified between 1993 and 2007. About 83 percent of these drug-resistant cases involve immigrants born abroad.

"California, having so much exposure to the world via immigration and travel, is particularly at risk," said Gil Chavez, deputy director of the California Department of Public Health.

Patients with multidrug-resistant tuberculosis do not respond to the most commonly used antibiotics. Of even greater concern is extensively drug-resistant tuberculosis, which is even more resistant to an even greater number of drugs, making treatment extremely difficult.

A statewide analysis of drug-resistant TB cases between 1993 and 2006 found the proportion of patients that were one drug away from becoming extensively drug resistant grew from 7 percent to 33 percent.

"It's a wake-up call," said Ritu Banerjee, a researcher with the Division of Infectious Diseases at the University of California-San Francisco and lead author on the paper published in the Clinical Infectious Diseases journal in 2008.

With extensively resistant TB, the patient can lose lung tissue and need surgery, pushing the cost of treatment up to $1 million, with no guarantee of survival, said Kenneth Castro, director of the Centers for Disease Control's Division of Tuberculosis Elimination.

"You get a couple of these patients and you can bankrupt a city program," he said.


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