New test can spot resistant tuberculosis faster

A team of British researchers has developed a new technique that reduces the time from weeks to days in genetically sequencing the bacteria causing tuberculosis.

"This could help health service providers to better treat disease, control transmission of this infection and monitor outbreaks," said scientists from University College London.

"Using the conventional methods, patients with resistant TB would need to wait for up to six weeks for antibiotic resistance testing," said senior author professor Judith Breuer from University College London.

"Our technique and the associated software could reduce testing for antimicrobial resistance to a few days, allowing doctors to give precise antimicrobial treatment earlier than is currently possible," Breuer noted.

The whole genome sequencing reveals the complete genetic (DNA) sequence of an Mtb sample, in many cases pinpointing drug resistance mutations so that appropriate treatments can be given.

The new method allows scientists to enrich Mtb DNA directly from patient sputum (mucus) samples. The samples can be sequenced and analysed straight away, avoiding the need to spend weeks growing them in the lab.

To extract Mtb from sputum samples, the researchers used probes made of ribonucleic acid (RNA) molecules, engineered to bind to Mtb DNA. The sequencing results from sputum matched perfectly with those from the relevant cultured isolates.

"As well as delivering personalised treatments to patients, the tests could also be used to precisely track the spread of TB," explained co-lead author Josephine Bryant from UCL Infection & Immunity).

The study was published in the Journal of Clinical Microbiology.