[afro-nets] New Drug-Resistant TB Strain Poses Challenges

[Claudio Schuftan <claudio@hcmc.netnam.vn>]

New Drug-Resistant TB Strain Poses Challenges
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Wall Street Journal (03.24.06): Betsy McKay

In a survey of 25 TB laboratories on six continents, CDC and the
World Health Organization (WHO) reported today that a growing
percentage of TB cases are multidrug-resistant (MDR-TB) and even
"extensively drug-resistant" (XDR-TB). MDR-TB is resistant to
the two most commonly used drug treatments, while XDR-TB strains
are resistant to even most second-line drugs.

In the survey, XDR-TB rose from 5 percent of MDR-TB cases in
2000 to 6.5 percent of MDR-TB cases in 2004, or 2 percent of pa-
tient samples tested. Although XDR-TB was found in the United
States, it was reported most frequently in South Korea, Eastern
Europe, and Central Asia, CDC said. One concern is that, with
fewer drug options, such patients could be facing "pre-
antibiotic" era treatment methods, such as the removal of in-
fected parts of the lung, said Kenneth Castro, assistant surgeon
general and director of CDC's division of TB elimination.

While TB cases have declined in the United States, the trend has
decelerated in tandem with funding cuts to TB control measures,
said Castro. The proportion of MDR-TB cases has increased after
more than a decade of general declines. In 2004, MDR-TB cases
increased 13.3 percent in the United States, to 128 diagnoses,
or 1.2 percent of all cases tested. Of those, 97 were foreign-
born persons from countries including Mexico, the Philippines,
and Vietnam, said CDC.

Drug-resistant TB emerges when patients do not complete treat-
ment or the regimen is ineffective for the strain. According to
WHO, of about 9 million new active TB cases diagnosed worldwide
each year, about 400,000 are MDR-TB. Worldwide, 2 million people
die annually from TB, which infects one-third of the 40 million
people with HIV. Six new TB drugs will be tested soon in humans,
possibly opening other options for treating drug-resistant
strains, said CDC.

The full report, "Emergence of Mycobacterium tuberculosis with
Extensive Resistance to Second-Line Drugs - Worldwide, 2000-
2004," was published in Morbidity and Mortality Weekly Report