A DNA sequencer the size of a USB stick promises to revolutionize clinical diagnosis

Novel methods of DNA sequencing have been revolutionizing biology for the last two decades. But much of the development has been in high-throughput methods that generate many short DNA reads, making the genome sequence difficult to assemble if it contains repetitive sequences like those often flanking newly acquired antibiotic resistance genes in some bacterial pathogens. 

A new report from a team of scientists, led by Justin O’Grady of the University of East Anglia, uses a new ‘long-read’ DNA sequencing device called MinION to identify how a strain of the bacterium responsible for causing typhoid has become resistant to multiple antibiotics. The team, including Salvatore Rubino of the King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia, found the island of antibiotic resistance genes in Salmonella Typhi H58 in just 18 hours, they report in Nature Biotechnology¹. 

“This analysis would previously have taken months using traditional methods, due to extensive post-sequencing lab-based analysis,” says O’Grady.

MinION uses nanopore DNA sequencing technology, in which strands of DNA are passed through pore proteins embedded in a membrane across which an electric voltage is applied. Tiny fluctuations in the current are indicative of the sequence of DNA bases passing through the pore. MinION sequencers are only the size of a USB stick and will be available next year at around £650. 

“This type of technology makes next generation sequencing accessible to scientists everywhere,” says O’Grady. “MinION technology could potentially enable bacterial identification, diagnosis of infectious diseases and detection of drug-resistance at the point of clinical need.” 

Sign-up to receive our e-alert update every two weeks to keep up with everything new on the portal.