The facts: Tuberculosis (TB) is the ninth leading cause of deaths from a single infectious agent, Mycobacterium tuberculosis causing 1.8 million deaths worldwide in 20151. According to the World Health Organization drug-resistant TB is on the rise with a total of 490,000 people infected with a multidrug-resistant tuberculosis (MDR-TB) strain in 20161. Superfluous use of antibiotics has given rise to multidrug resistant bacteria These ‘superbugs’ have become one of the major global public health threats. Precise and timely detection of the causative agent followed by the appropriate antibiotic treatment is an imperative aspect in combating MDR infections and could help in reducing fatalities in diseases like TB. Currently, the methods used for detecting an active TB infection include chest X-rays (for pulmonary TB), microscopic test, microbiological culturing and molecular methods. The culture-based methods can take several days before a result is confirmed. On the other hand, quicker molecular detection can be expensive to perform and are not easily accessible to patients from all socioeconomic backgrounds. Cheaper and rapid detection methods are needed to help bridge the gap between detection and treatment.

The science: M Kamariza and group developed a chromogenic assay based on the sugar trehalose for the detection of Mycobacterium tuberculosis. This simple dye based staining technique employs the use of trehalose conjugated 4-N,N-dimethylamino-1,8-napthalimide (DMN) to make DMN-Tre. Trehalose is a part of the outer membrane of the bacterial cells which upon staining with DMN-Tre take up the molecule and emit fluorescence. Because this molecule can be incorporated only by cells that are metabolically active, the test can distinguish between viable and non-viable bacteria in the sample. Preliminary data from this study also suggests that this method could be used for drug sensitivity screening. However future studies are warranted.

The potential: This test uses membrane properties unique to Mycobacterium and is thus specific also providing information about metabolic state of the bacterial cells. The primary reagent, DMN-Tre is shelf stable for weeks and the test can be performed with minimal chemicals and equipment. This inexpensive one-step point of care diagnostic test could prove to be a boon for clinical labs in economically challenged regions and is a promising step towards effectively managing the diagnosis and cure for tuberculosis.

 

References:

  1. World Health Organization (WHO) http://www.who.int/tb/en/
  2. Kamariza et al. “Rapid detection ofMycobacterium tuberculosis in sputum with a solvatochromic trehalose probe.” Science Translational Medicine. Published online February 28, 2018.

Author

Snehal Joshi 

 

Cover Image Photo by Drew Hays on Unsplash

Future is sweet

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