Rapid molecular diagnostic test for drug-resistant tuberculosis may help save lives

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26 May 2016

The internationally adopted first-line treatment for tuberculosis (TB) is with the drugs isoniazid, rifampicin, pyrazinamide and ethambutol. Resistance of Mycobacterium tuberculosis to at least the best two of these drugs, isoniazid and rifampicin, is called multidrug-resistant tuberculosis (MDR-TB), and has caused a global public health crisis. Patients with MDR-TB or with rifampicin resistance alone are treated with fluoroquinolones and injectable second-line drugs. Inappropriate drugs may be prescribed because culture-based testing of second-line drug susceptibility can take months.

On 12 May 2016 the World Health Organization (WHO) recommended that a novel molecular line probe assay that detects resistance to second-line TB drugs should be used by national TB laboratories to improve the treatment of MDR-TB and rifampicin-resistant TB. The test, the GenoType MTBDRsl assay (Hain Lifescience, Nehren, Germany), takes just 24 – 48 hours rather than months by culture-based methods, and so allows patients to be put on targeted MDR-TB regimes quickly. In addition, patients with no second-line TB drug resistance can be put on a shortened course of treatment.

Karin Weyer DSc, from the WHO Global TB Programme, said “We hope that the faster diagnosis and shorter treatment will accelerate the much-needed global MDR-TB response. Anticipated cost-savings from the roll out of this regimen could be re-invested to enable more patients to be tested and retained on treatment.”

FIND, a global non-profit organisation for accelerating the development, evaluation and delivery of high-quality, affordable diagnostic tests for poverty-related diseases, has negotiated a preferential price for the basic materials of the MTBDRsl assay in 138 countries.