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BOSTON (Reuters Health) - Two recent outbreaks of tuberculosis resistant to one or more standard drugs show no signs of slowing down, researchers reported at the 15th Conference on Retroviruses and Opportunistic Infection. Many cases in these outbreaks in Eastern Europe and Africa are complicated by HIV infection, and call for "urgent" prevention measures.
Dr. Neel Gandhi of the Albert Einstein College of Medicine in the Bronx, New York, described an outbreak of multidrug-resistant tuberculosis (MDR-TB), including some cases of extensively drug-resistant tuberculosis (XDR-TB) among HIV-infected individuals living in a rural population in KwaZulu-Natal, South Africa.
The outbreak began in 2005 and is continuing to grow.
HIV-infected patients are the "canaries in the mines," Gandhi said. They provide the first sign that MDR-TB is circulating in the population because they are among the first to become infected, he explained.
Gandhi's group observed a pattern in which patients infected with HIV and TB would relapse with resistant TB soon after initially successful TB treatment. Between 2005 and 2006, his group evaluated 17 patients with HIV and TB who were beginning to show signs of TB drug resistance.
The evidence pointed to transmission of a new resistant TB strain as the source of re-infection, rather than mutation of the original TB strain. Survival among the 17 patients was poor, with 15 dying within weeks of diagnosis with resistant TB.
Although the need for improving treatment programs and cure rates remains important, Gandhi said, these findings illustrate the vital role of infection control, which will require more attention before the outbreak can be controlled.
In a second report, Dr. Matteo Zignol, of the World Health Organization's Project Office in Donetsk, described a MDR-TB outbreak in a more urban population of 47 million in Ukraine, which has the highest rates of HIV and TB in the region.
Zignol's group studied all new and previous TB cases over a 1-year period. Of about 1500 cases, two thirds were new cases and one third had been previously treated for TB. Twenty-one percent of the patients also had HIV.
