JOHANNESBURG, South Africa - Doctors said Thursday that a genome for one strain of an extensively drug-resistant tuberculosis has been sequenced -- a finding they say could help fight the deadly disease.

Doctors mapped the bacteria in a week using technology developed in the United States, said Dr. Carl Montague of LifeLab, a biotechnology project funded by the South African government.

"We consider this a breakthrough because it will provide for more analysis of MDR (multi drug-resistant TB) and XDR-TB (extensively drug-resistant TB), and to understand the differences between them," Montague said.

The complete genome sequencing data has not yet been shared with other scientists. Previous tuberculosis strains have already been mapped, and some experts are uncertain how quickly the research will result in new diagnostics or treatments.

"This is just one strain," said Dr. Mario Raviglione, director of the World Health Organization's Stop TB department. Raviglione said there are hundreds of strains of XDR-TB, and that even if a new diagnostic test was developed from this genome, it would probably only work for that specific strain.

"Mapping the genome may open up interesting ways to look at the bacteria, but we are far from having any new tests or treatments," he said.

Last year, the World Health Organization announced an outbreak of XDR-TB in South Africa in which all but one of the 53 patients confirmed with the strain died. To date, more than 300 cases have been identified, and at least 30 more are reported each month.

About 330,000 South Africans have TB, and 6,000 have a multiple drug-resistant variant, officials said. Extensively drug-resistant tuberculosis exists worldwide, including in eastern Europe, Russia and the United States.