Tuberculosis Becoming More Drug-Resistant

By DAVID BROWN

WASHINGTON – About one in every 20 new cases of tuberculosis worldwide is now resistant to two or more drugs, and in some regions of the former Soviet Union the proportion is closer to one in every five cases, the World Health Organization reported Tuesday.

In addition, "extensively drug-resistant" tuberculosis (XDR-TB), a relatively new subtype of the disease that takes $15,000 in drugs and two years to treat, has now been found in 45 countries. TB epidemiologists estimate 40,000 new cases emerge each year, and the death rate in untreated or poorly treated cases is close to 100 percent.

"Multi-drug resistant" tuberculosis (MDR-TB) could account for 22 percent of all cases in Baku, Azerbaijan and 19 percent of Moldova’s, a rate that "was not thought to be possible" in the 1990s, said Mario Raviglione, the head of WHO’s tuberculosis department, who will discuss the data Wednesday in a congressional hearing.

"The speculation was that it wouldn’t go over 10 percent," he said. The assumption was that the drug-resistant strains would be seen almost exclusively in AIDS patients and other people with weakened immune systems, but it is now clear that once MDR bacteria emerge – almost always because of inadequate or improper treatment – they can circulate easily in the general population.

"The Azerbaijan data just blew me away," said Richard Chaisson, head of the Center for Tuberculosis Research at Johns Hopkins University School of Medicine.

Normally, tuberculosis is treated with four drugs for at least six months. MDR strains are resistant to the two most commonly used medicines, rifampin and isoniazid. XDR-TB is resistant to those two and at least two others of different types.

The new data were compiled from national, regional and city surveys. Because the list of countries surveyed differs from previous reports, it’s impossible to say whether the estimate that 4.8 percent of all TB cases are MDR or XDR is an increase or decrease from a few years ago.

"What is fair to say is that what we are seeing globally now is different from what we were seeing a decade, or a decade and a half, ago," Chaisson said.

Around the world there are about 9 million new cases of tuberculosis each year and about 1.6 million deaths from it (out of 62 million deaths from all causes).

The disease, which usually attacks the lungs, is second only to AIDS in deaths from infectious illness.

MDR strains accounted for more than 6 percent of new TB cases in 14 regions. They included Georgia and two regions of China (7 percent); Armenia (9 percent); Latvia (11 percent); the city of Tashkent in Uzbekistan (15 percent); and the Donetsk region of Ukraine (16 percent).

Originally published by THE WASHINGTON POST.

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