Phelix is working on a new rapid and highly sensitive phage based diagnostic method, testing blood and/or urine samples to detect Borrelia spp.
Why do we need a new diagnostic test to detect Borrelia spp.?
Diagnostic techniques for an infection of Borrelia species remains a controversial topic. Doctors can find it difficult to diagnose a Borrelia infection due to the non-specificity of symptoms, which often overlap with symptoms of multiple other conditions.
The most distinct symptom of Lyme disease, caused by Borrelia infection, is erythema migrans otherwise known as the bullseye skin rash. However, this is not seen in every case and many patients do not recall having seen this rash.
Misdiagnosis through the use of tests with low sensitivity can lead to chronic infection which, if it goes unchecked, can lead to complications in the heart, musculoskeletal system and even the brain and nervous system.
The current diagnostic system is estimated to misdiagnose around 54% of patients.
| Lyme diagnostics | Target | Remit of the diagnostics |
|---|---|---|
| ELISA/Western Blot | Borrelia-specific antibodies | - Provide indirect evidence of the presence of Borrelia - Specific, but less sensitive - Can't distinguish active and non-active Borrelia - Can't distinguish among different Borrelia sub-types |
| Bacterial PCR | 16S rRNA or other bacterial DNA | - Detect the presence of Borrelia DNA - Highly specific, low in sensitivity - Can't distinguish active and non-active Borrelia - Can't distinguish among different Borrelia sub-types |
| Lymphocytes transformation test (LTT) | Borrelia-specific T helper lymphocytes | - Provide indirect evidence of the presence of Borrelia - Specific, variable in sensitivity - Can only detect lymphocytes that have benn in contact with Borrelia within 45+/-15 days, thus limited in application - Can't distinguish among different Borrelia sub-types |
| Phelix Phage-based test | Phages residing inside Borrelia | - Can provide direct evidence of active Borrelia presence - Highly specific and sensitive - Can distinguish Lyme from relapsing fever Borrelia strains - Further development will allow diagnosis of early Lyme, and differentitation of different Borrelia sub-types |
Current diagnostic methods for Borrelia spp. detection
-
- Enzyme-linked immunosorbent assay (ELISA) test:
ELISA detects antibodies to Borrelia. It can sometimes provide false-positive results, and so is not used as the sole diagnostic test. It is often not positive during the early stage of infection, as the antibodies to the bacteria may not be present in a high enough quantity to affect the test as they may not yet be developed or the bacteria may be suppressing their production.
- Enzyme-linked immunosorbent assay (ELISA) test:
-
- Western blot test:
If the ELISA test is positive or inconclusive, this test is done to confirm the diagnosis. In this two-step approach, the Western Blot detects antibodies to several proteins of Borrelia burgdorferi, the most common disease causing species of Borrelia.
- Western blot test:
- PCR:
PCR can also be used for specific detection of DNA or RNA of pathogenic organisms, in this case Borrelia burgdorferi.
Most tests focus only on one strain of bacteria which can lead to patients receiving a false positive test result.
These tests also may detect antibodies to Borrelia burgdorferi in the blood even if the bacteria are no longer present.
The review below provides a comprehensive assessment of the development and application of currently available tests for the laboratory diagnosis of Lyme Borreliosis. Future directions for improvement of established tests and for development of new approaches are also discussed.
Where does Phelix come in?
Phelix has set up a new phage based PCR for Borrelia spp. which has an increased sensitivity by 50% when compared to current available tests.
It has also been experimentally confirmed that our phage-based PCR showed significantly increased sensitivity compared to the traditional 5S-23S intergenic region based PCR. As seen in the gel picture below, only one positive (IV) using bacteria-based PCR, while two positives can be identified using phage-based PCR.
A Borrelia 16S nested PCR was also developed, which involved a bacterial universal PCR followed by a Borrelia PCR. This PCR will pick up all Lyme Borrelia strains.
