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Rapid whole-genome sequencing reduces time taken to diagnose XDR tuberculosis

By 18 de July de 2013November 18th, 2020No Comments
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A 3D model of the alanine racemase protein which shows the mutation that causes the resistance to therapy. Source: CNAG.
 18.07.2013

Rapid whole-genome sequencing reduces time taken to diagnose XDR tuberculosis

Marc A. Marti-Renom, researcher from the –based in the Parc Científic de Barcelona– and the Centre for Genomic Regulation (CRG), has participated in a study that reveals the potential of rapid whole-genome sequencing in a hospital setting to reduce the time taken to diagnose extensively drug-resistant (XDR) tuberculosis from weeks to days.The work –published as a Letter to the Editor in the journal The New England Journal of Medicine ()– reported a finding that might guide clinicians and reference laboratories in the identification of drug resistant tuberculosis.


The study, led by researchers from the University of Cambridge and Public Health England, started when a 38-year old male patient had a first admission to a hospital with clinical and radiological features consistent with pulmonary tuberculosis. Current laboratory methods of identifying and typing Mycobacterium tuberculosis complex (causative agent of most cases of tuberculosis) were performed. In parallel, DNA was extracted from the sample and sequenced with the use of the Illumina MiSeq platform.

The results of rapid whole-genome sequencing revealed a mixed infection caused by two distantly related Beijing strains of M. Tuberculosis that was not apparent with the standard laboratory techniques. It also identified that the second strain, which was responsible for the 30% of the bacteria present in the patient, had a mutation in a gene targeted by antibiotics. The 3D modelling of the mutated protein structure strain, performed by the CNAG and CRG researcher Marc A. Marti-Renom, helped to better understand the molecular mechanisms that underlie XDR tuberculosis.

The study suggests that rapid whole-genome sequencing complements current methods for identifying and typing M. tuberculosis complex offering the ultimate molecular resolution in a hospital setting.

The CNAG was created in 2009 with support from the Ministry of Science and Innovation and the Government of Catalonia as a platform integrated into the Barcelona Science Park. The mission of the centre is to carry out large-scale DNA analysis and sequencing projects in collaboration with researchers from Catalonia, Spain and other parts of the world and ensure the international competitiveness of our country in the strategic area of genomics.

The centre, directed by Dr. Ivo Gut, has a highly-qualified team of 55 (50% of the staff hold doctorates), and a fleet of 13 latest-generation sequencers, which have allowed it to achieve a sequencing capacity of up to 600 Gbases/day, equivalent to sequencing six human genomes per day. This makes the CNAG the second ranked European centre for sequencing capacity.