With a new test developed by a team at University College London (UCL), the detection time for tuberculosis (TB) may be reduced to a few days rather than a week or more. The test can genetically sequence tuberculosis bacteria (Mtb) from samples much faster than traditional testing methods.
TB is spread through the air contaminated with the Mycobacterium tuberculosis. The Centers for Disease Control and Prevention (CDC) recommends TB testing for people:
- who have spent time with TB patient
- with HIV infection or another medical problem that weakens the immune system
- who have symptoms of the disease
- from a country where the disease is common
- who use illegal drugs
Two tests are currently used to help detect latent TB infection – a skin test and a blood test. While the skin test checks the person’s risk of being infected and the progression to the disease, the blood test measures how the person’s immune system reacts to the bacteria that cause TB. The ELISA test for TB offers a high degree of sensitivity.
The new testing method developed by the UCL team allows the enriching Mtb DNA directly from patient sputum samples. This means that the samples can be sequenced and analyzed immediately, so that there is no need to spend weeks culturing them in the lab. The method was tested on 34 routine samples taken from patients in London and Lithuania, where resistant Mtb strains are a major problem.
According to a report on the UCL team’s discovery, the new test will allow physicians to begin the specialized treatment for the disease sooner than before, as it will tell them in just a few days whether the strain is drug resistant. The researchers point out that the test can help physicians:
- Treat the disease earlier
- Provide personalized treatments to patients
- Precisely track the spread of TB
- Allow rapid sequencing so that TB infections can be traced in communities
- Identify ‘super-spreaders’ (a few highly infectious people)
- Stop the disease from spreading
- Control and prevent future outbreaks
The technique has also been applied to other infections including chlamydia, HIV, hepatitis, herpes, influenza A, norovirus and cytomegalovirus. The team hopes to further process the technique, making it more cost-effective and simpler for practical use in less economically developed countries where drug-resistant TB is common.