New Method for Detecting Tuberculosis Bacteria
A recently published study presents a novel and more sensitive approach to identify the bacteria that cause tuberculosis (TB). TB, a serious disease affecting numerous countries, is triggered by the bacterium Mycobacterium tuberculosis (Mtb). Although effective treatments are available for TB patients, the emergence of drug-resistant Mtb strains has complicated the global health crisis in recent years.
Challenges in Tuberculosis Diagnosis
The swift diagnosis of TB has been facilitated by various tests developed over the past 80 years. These tests typically rely on the absorption of dye by the outer membrane of Mtb bacteria. However, the sensitivity of these tests can fluctuate due to the dye’s tendency to bind with debris and other bacterial species. Moreover, existing diagnostic methods fail to distinguish between live and dead or dying mycobacteria, hindering clinicians’ ability to evaluate treatment effectiveness and provide optimal care. Therefore, there is a pressing need for advanced tools that enhance diagnostic accuracy and specificity for viable Mtb detection.
Research Approach and Findings
Researchers identified specific chemicals vital for Mtb’s survival that are incorporated into the bacterial outer membrane. An American research team focused on a fluorescent probe designed to light up upon integration into the membranes of live bacteria. Their findings, published in Science Translational Medicine, describe an innovative and straightforward labeling method for Mtb.
Role of Trehalose in Detection
Trehalose, a compound absorbed by Mtb, was examined for its specificity by analyzing bacterial strains with the necessary enzymes to metabolize trehalose using a national bacterial database. The researchers found that only a limited group of bacterial strains possessed these enzymes, excluding common lung bacteria such as Pseudomonas and Streptococcus.
Subsequently, the authors conjugated a unique fluorescent dye to trehalose, which fluoresced upon incorporation into the bacterial membrane. Testing this synthesized fluorescent probe on various bacterial strains revealed that only those capable of processing trehalose emitted fluorescence. Notably, fluorescent signals appeared within five minutes after adding the probe to different mycobacteria strains. In instances where these strains were heat-killed or treated with TB medications, the fluorescence diminished accordingly. The probe was also tested on pathogenic Mtb cultures and sputum samples from TB patients, successfully detecting Mtb in both scenarios, highlighting its potential for clinical application.
Implications for Tuberculosis Testing
The current technology for detecting Mtb in TB patients is considerably outdated, and the limited sensitivity of existing tests can adversely affect clinical treatment and understanding of the disease. The described method allows for Mtb detection in under five minutes using a simple labeling technique. Additionally, this test is specific to mycobacteria and can differentiate between live and dead or drug-compromised bacteria. This innovative probe not only aids in identifying tuberculosis infections but also assesses drug sensitivity. However, larger clinical studies are needed to confirm the probe’s effectiveness. The encouraging results from this study suggest that this new technology could significantly improve TB diagnosis and treatment in the future.
Written by Branson Chen, BHSc
Reference: Kamariza M, Shieh P, Ealand CS, Peters JS, Chu B, Rodriguez-Rivera FP, et al. Rapid detection of Mycobacterium tuberculosis in sputum with a solvatochromic trehalose probe. Sci Transl Med. 2018 Feb 28;10(430):eaam6310.