Los Angeles Times - February 27, 2008
Thomas H. Maugh II

The WHO report, the first new survey of TB incidence in four years, estimates there are nearly 500,000 new cases of multidrug-resistant TB, commonly known as MDR-TB - about 5 percent of the 9 million total cases of TB each year.

The highest rate was recorded in Baku, Azerbaijan, where 22.3 percent of all new cases were MDR. Rates of 14.8 percent or higher were also found in Moldova, the Donetsk province of Ukraine, the Tomsk province of the Russian Federation and in Tashkent in Uzbekistan.

MDR-TB also was found in a high proportion of cases in China's inner Mongolia and Heilongjiang regions.

In contrast, the highest rate reported in the 2004 survey was 14.2 percent in Kazakhstan.

Experts attributed the high incidence in those regions to poverty, congestion, alcoholism and stress form the dismantling of the Soviet Union.

Surprisingly low rates of drug-resistant strains were found throughout most of southern Africa, which has the highest rates of TB in the world - although many countries were unable to report data because of the lack of sophisticated laboratories to test for the variants.

Dr. Mario Raviglione, director of the WHO's Stop TB department, attributed the low incidence to the overall lack of treatment in the region. If the majority of people are not getting antibiotics, he said, the TB bacteria will not develop resistance to them.

"But with the more widespread use of rifampicin and other drugs (in recent years), the situation is going to go more quickly out of control because of the presence of HIV," which leaves victims much more susceptible to TB, he said.

Tuberculosis is an infection of the lungs characterized by fever, weight loss, night sweats and coughing up blood.

The disease is spread primarily through microscopic droplets released when an infected person coughs, sneezes or speaks.

The MDR variety of the disease is resistant to two first-line antibiotics, isoniazid and rifampicin. Treatment can take as long as two years, compared to six months for conventional TB. The drugs used are more toxic and 100 times more expensive.

An even more serious form, known as extensively drug-resistant TB, commonly called XDR-TB, is resistant to both of those antibiotics and to fluoroquinolones and any of the injectable antibiotics, such as kanamycin or capreomycin. Treatment may require surgical removal of part of the lungs, and some strains are virtually untreatable.

The WHO survey found that XDR-TB has now been detected in 45 countries.

Drug-resistant strains of TB develop when patients do not complete their course of treatment, allowing mutated versions of the bacterium to emerge. These new strains can then be passed from person to person, just like the older ones.

There were 111 cases of MDR-TB and three cases of XDR-TB in the United States in 2006, according to the Centers for Disease Control and Prevention.

Only a few years ago, scientists dismissed drug-resistant TB as a major threat. Most thought it could occur only in HIV-positive patients whose immune systems were suppressed, and they also believed that the development of resistance lowered the pathogenicity of the bacterium and impaired its ability to spread.

Now, Raviglione said, both of those ideas have been shown to be wrong.

The major problem in improving control is money. The WHO estimates that $4.8 billion a year is needed for overall control of TB in low- and middle-income countries, with about $1 billion of that directed toward drug-resistant strains.

But only half that amount is available, according to the report.

"The threat created by TB drug resistance demands that we fill these gaps," said Dr. Marcos Espinal, executive secretary of the Stop TB Partnership, a network of more than 500 international organizations dedicated to eliminating TB.

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