Use of Specific Borrelia Phages as a New Strategy for Improved Diagnostic Tests

The high failure rate of tick-borne infection (TBI)-related testing underscores the need for novel approaches that do not rely on serology and two-tier testing. Delayed diagnosis of TBIs, especially Borrelia infections, results in high healthcare costs and great suffering. There is a significant need for a reliable blood test that can aid in the diagnosis of Lyme disease, particularly when the current FDA-approved serological test is not sensitive enough to detect early Lyme patients who have not yet produced antibodies against Borrelia. Bacteriophages are viruses that specifically associate with their bacterial hosts, particularly prophages, bacteriophages residing in bacteria, and have proven to be tightly correlated with their bacterial hosts. They are poised to have wider applications as markers to detect bacteria, particularly in infectious disease. The gene of choice depends on the prevalence of phages within a particular group of bacteria. Phage genes that have been used as molecular markers to examine phage diversity include structural genes encoding the major capsid protein, the portal protein, the DNA polymerase, and the terminase. Borrelia species carry specific phage sequences that can be used as a proxy to identify the bacteria. Using phages as a proxy for bacteria is beneficial, as phages can be detected more easily than bacteria and can be used to bypass the cryptic and tissue-bound feature that typifies human Borrelia infections. We explored a completely new way of detecting Borrelia using Borrelia-specific bacteriophagesBacteriophages as a diagnosticDiagnostics tool. Our detection method, patented by Phelix R&D and Leicester University (WO2018083491A1), could potentially transform infectious diseaseInfectious diseases diagnosticsDiagnostics through the innovative use of real-time PCRPolymerase chain reaction (PCR) to target circulating bacteriophageBacteriophages DNA in blood from patients with Lyme diseaseLyme disease. Firstly, this bacteriophage-based approach offers increased sensitivitySensitivities since bacteriophagesBacteriophages are typically present in five- to tenfold excess over bacterial cells, making it more accurate and sensitive than conventional bacteria-targeting PCRPolymerase chain reaction (PCR) tests. One of the reasons bacteria-based PCRPolymerase chain reaction (PCR) tests are frequently negative is due to the low bacterial concentrationConcentrations in the blood. Bacteriophage-based PCRPolymerase chain reaction (PCR) surpasses this barrier and offers a direct test, as phages are part of bacteria’s own genetic material, in contrast to all existing indirect tests (ELISAIndirect Enzyme-linked Immunosorbent Assay (ELISA), Western BLOT, LTT/ELISPOTEnzyme-linked immunosorbent spot (ELISpot) test). Secondly, a phage-based test can differentiate between different Lyme disease-causing and relapsing fever-causing Borrelia subtypes (B. burgdorferi s. l., B. miyamotoi, etc.), given that bacteriophagesBacteriophages are indicators of bacterial identity. Finally, this test can detect Lyme diseaseLyme disease in both early and late stages.