Mycobacterium tuberculosis is the most deadly bacterium on this planet. According to the World Health Organisation, 2016 saw 10 million people newly diagnosed with TB. And 1.7 million people died from the disease. One factor may be the difficulty in TB testing. And a quick, cheap, accurate TB test could make a big difference in those big numbers.
The Problems with Current Tests
There are three basic tests for TB.
Sputum smear test:
- Takes time to process
- Not very accurate – needs 10,000 bacteria for accuracy (especially inaccurate for those who have both TB and HIV)
- Can’t distinguish between living and dead bacteria (so hard to tell if treatments are working)
Culturing (growing TB in the lab):
- Slow test because TB grows slowly (can take up to 42 days)
- Difficult to accomplish with limited resources
Molecular diagnostics, used for detecting the DNA of the bacteria:
- Expensive
- Can’t distinguish between living and dead bacteria (so hard to tell if treatments are working)
What We Need
- Faster diagnostics: treatment starts earlier (good for the patient), earlier awareness of the risk of transmission (good for everyone else)
- Distinguish living from dead cells: to see if cells are dying off, if treatment is working
- Cheaper and easier: to perform tests in bulk and for people with few resources
So we need basic quick, cheap, accurate TB test.
The Breakthrough
They’ve invented it. They’ve tested it. It seems to work. And it’s clever.
The TB bacteria create their cell walls with a chemical (trehalose) unique to them. Dr. Carolyn Bertozzi, Stanford University, developed a combination called DMN-trehalose using trehalose and a chemical that changes color and fluoresces.
So it’s colorless until the bacteria build it into their cell walls (which they do because it is partly trehalose). Then it lights up.
Conclusion
A quick, cheap, accurate TB test could make testing a reality for the millions of people at risk of contracting TB right now.
