By David Brown
Washington Post Staff Writer
Friday, March 24, 2006
The number of cases of multidrug-resistant tuberculosis is increasing in the United States, as is the fraction of those cases that is resistant to at least five antimicrobial drugs.
The Centers for Disease Control and Prevention reported that there were 128 cases of multidrug-resistant TB in the United States in 2004, up from 113 the year before. This is the first increase in a decade.
In addition, the proportion of hard-to-treat cases that are "extensively drug resistant" rose from 3.9 percent in the 1993-1996 period to 4.5 percent during 2001-2004.
"It is a modest increase, but it is a movement in the wrong direction," said Kenneth G. Castro, an assistant surgeon general and director of the tuberculosis program at the CDC, which released the data.
These findings appear to be driven by the growth of multidrug-resistant (MDR) TB overseas and in recent immigrants to the United States. .
Of the 2005 cases, 45 percent were in U.S.-born people, and the balance in foreign-born people. The most frequent native countries of the latter group were Mexico, the Philippines, Vietnam, India, and China.
Overall, tuberculosis continues to decline in this country. The per-capita rate of the lung infection last year was the lowest since the government began collecting data in 1953. There were slightly more than 14,000 cases reported to health authorities, compared with about 24,000 a decade earlier.
The incidence of TB has fallen steadily since 1993, when a seven-year rise of the disease finally got the attention of public health authorities who had considered it virtually eliminated.
That resurgence was marked by outbreaks of multidrug-resistant infections, particularly among prisoners. Castro said he and other officials hope the slight uptick in MDR cases now is not the harbinger of a new phase of growth in the ancient infection.
The report, timed for World TB Day today, also described the growth of "extensively drug-resistant" (XDR) TB, defined as microbes resistant to not only the two first-line drugs, but to three or more of the six classes of second-line drugs.
Laboratory studies from Latvia showed that 19 percent of drug-resistant cases fit the XDR definition, as did 15 percent of the drug-resistant cases in South Korea.
"Drug-resistant TB is growing, and that should worry us," said Marcos Espinal, a World Health Organization official who heads the Global Partnership to Stop TB.
On a telephone briefing organized by the anti-poverty activist organization, Results, he called for more money to fight the global TB epidemic, which is particularly severe in sub-Saharan Africa because of the disease's high incidence in people infected with the AIDS virus.