New DNA sequencing technique to improve TB diagnosis

Tuberculosis diagnosis has got a major boost with scientists developing a new approach that relies on direct sequencing of DNA extracted from sputum to detect and characterise the bacteria that cause the disease.
Researchers working in the UK and The Gambia, developed a new approach to the diagnosis of tuberculosis (TB) that relies on direct sequencing of DNA extracted from sputum (a technique called metagenomics) to detect and characterise the bacteria that cause TB without the need for time-consuming culture of bacteria in the laboratory.
"Laboratory diagnosis of TB using conventional approaches is a long drawn-out process, which takes weeks or months," said Mark Pallen, Professor of Microbial Genomics at Warwick Medical School in UK.

"Metagenomics using the latest high-throughput sequencing technologies and some smart bioinformatics, allows us to detect and characterise the bacteria that cause TB in a matter of a day or two, without having to grow the bacteria, while also giving us key insights into their genome sequences and the lineages that they belong to," said Pallen.
"TB is still a big problem in Africa and across the world. It is exciting to be involved in the development of new diagnostic approaches for this deadly disease," Dr Martin Antonio, head of the TB diagnostics laboratory at the Medical Research Council (MRC) Unit in The Gambia, said.

The team detected sequences from the TB bacteria in all eight sputum samples they investigated and were able to assign the bacteria to a known lineage in seven of the samples.
Two samples were found to contain sequences from Mycobacterium africanum, a variety of the TB bacterium that is particular to West Africa.
The study was published in the journal PeerJ.