TB genomes recovered from mummy
The researchers were able to look at this TB genome, a mix between two different strains of the TB bacterium. Looking at this older sample of TB alongside new cases showed the significance of mixed strain TB and may give doctors and researchers a better understanding of mixed strains.
"Most other attempts to recover DNA sequences from historical or ancient samples have suffered from the risk of contamination, because they rely on amplification of DNA in the laboratory, plus they have required onerous optimization of target-specific assays," Pallen said. "The beauty of metagenomics is that it provides a simple but highly informative, assumption-free, one-size-fits-all approach that works in a wide variety of contexts."
The team recovered the TB sample from lung tissue using a technique called metagenomics. Metagenomics uses open-ended sequencing and doesn't require cultures or target-specific amplification.
"It was fascinating to see the similarities between the TB genome sequences we recovered and the genome of a recent outbreak strain in Germany," Pallen said. "It shows once more that using metagenomics can be remarkably effective in tracking the evolution and spread of microbes without the need for culture -- in this case, metagenomes revealed that some strain lineages have been circulating in Europe for more than two centuries."
The research was published in the New England Journal of Medicine.