SA: Scientists Solve a Deadly TB Mystery

In 2005, 53 patients checked into a South African hospital with a severely antibiotic resistant strain of Tuberculosis, XDR TB, and only one survived. This was the largest reported outbreak for this strain and it remains the dominant form of TB in the KwaZulu-Natal province today. Recently, in an article in Proceedings of the National Academy of Sciences USA they discovered the origin of this strain. They believe their methodology could help identify other drug-resistant pathogens as they emerge to stop them from spreading. They used genomic sequencing of over 300 TB patients, and phylogenetic reconstruction that revealed when the mutation’s appeared and expanded. From this they learned that there were three major outbreaks. They combined this information with data from population genetics to visualize where the strain originated and migrated. This is significant because drug resistance is a growing, global issue. Researchers believe that applying whole-genome sequencing taken from patients, combined with an analytical approach similar to the one applied here, could help researchers detect worrying mutations before they become emergencies.

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