The technology platform – TOPO detection - presents a new concept that relies on an essential DNA modifying pathogen expressed enzyme (TopI) that is used as biomarker for infections. The use of essential enzymes as biomarkers ensures that only live pathogens are detected. Also, the fact that the assay detects pathogens directly rather than the immune response against pathogens in patients, adds further to optimize clinical decisions, since general health, time window after infection, vaccinations, age, gender or pregnancy will not affect the outcome of the test. Indeed early detection is very important in terms of treatment efficiency.
High sensitivity is anticipated due to the massive signal amplification inherent to the enzyme activity, as demonstrated previously . This is achieved by each target enzyme converting many (in theory infinite numbers) of substrate molecules to specific products, which are directly detected. The chosen enzyme target, the type I topoisomerases , is highly abundant in the plasmodium and mycobacteria cells with estimated copy numbers in the range of 100.000 in the examined cells , adding further to the expected sensitivity. Moreover, the target enzyme play essential roles for the pathogens rendering the risk for mutant stains that cannot be detected by TOPO detection extremely low or even zero.
The generic TOPO diagnostic platform is based on enzyme release using microfluidics, target identification and signal amplification followed by visual detection or read-out on paper. The concept can be integrated in one device suitable for point of care testing. Device requirement specifications will be validated in collaboration with FIND/WHO.
The TB diagnostics technology landscape has dramatically improved over the last years with several fully integrated tests aiming to reach the market. Nevertheless, despite the latest technological advancements and increasing diagnostic tools adoption, available methods are generally very costly and require extensive training skills, preventing their widespread adoption. In particular, the lack of both 1) a rapid, sputum-based, molecular test for microscopy centers and 2) a biomarker-based, low-cost, non-sputum-based test remain key priorities for an effective TB diagnostics.
Headlines of the results obtained - for details see attached slides:
The technology is slightly optimized in order to increse sensitivity (the basic principle is the same)
The TOPO-TB technology allows quantative detection
Different mycobacterial strains were all detected successfully using the TOPO technology
The TOPO-TB assay is specific to mycobacteria
Mycobacteria can be detected in samples mimicking saliva from TB patients
Conclusion: The TOPO-TB assay is fast, sensitive, specific and can be finally adapted to low respurce settings. The WHO requirements are fulfilled including the opportunity to detect TB from non-sputum samples.
