Researchers decode and post genome sequence for XDR TB strain

Researchers from Harvard and MIT, working with South African scientists, have decoded the first genome sequence of an extensively drug-resistant tuberculosis strain and have taken the unusual step of immediately posting the data online instead of first submitting them to a journal for publication, they said today.

The team from the Broad Institute of MIT and Harvard, the Harvard School of Public Health, and the University of KwaZulu-Natal are making available the genome sequence of a tuberculosis strain that has been linked to a particularly severe tuberculosis outbreak among patients with HIV in one South African town.

The scientists studied three TB strains in all: one that is sensitive to drugs, another that is resistant to multiple drugs, and the extensively resistant strain. They found differences in the genomes at only a few dozen locations among the 4 million letters of the viruses' DNA codes.

The hope is that these differences will reveal both drug resistance genes as well as genes that may be important in how TB is spread, leading to better testing and clues to treatments.

"We want to make this data available to all researchers, especially those who are working in endemic areas, so they can start to use it rather than wait for us," James Galagan, associate director of microbial genome analysis at the Broad, said in an interview.

The genomic information about this strain is important because diagnostic tests currently being developed to quickly detect drug resistance are based on gene sequence data, Megan Murray, associate professor at the Harvard School of Public Health, said in an interview.

"The idea is to make this information completely accessible so you don’t have to be a bioinformaticist to use it," she said. "It's kind of a new approach to doing science. If you make it available to everybody, you get a lot more brains thinking about it."