A pathologist based at a US hospital has found a new strain of Lyme disease using the polymerase chain reaction (PCR) and DNA sequencing. Found in a patient’s blood sample, the infectious agent was undetectable using standard Lyme disease lab tests.

Adult deer tick (Ixodes scapularis). Source: Agricultural Research Service

Adult deer tick (Ixodes scapularis). Source: Agricultural Research Service

Lyme disease symptoms include fever, headache, tiredness and a rash (erythema migrans), and this is generally caused by infection with the spirochete Borrelia burgdorferi, which is passed on via tick bites, though cases caused by Borrelia miyamoto were reported in the US in 2013. However, the clinical symptoms and detection of infectious agents can contradict each other, and other related bacteria are known to cause the same symptoms.

Pathologists at Milford Hospital looked at 52 blind-coded serum samples, including pre-treatment and post-treatment samples from clinically-suspect Lyme disease. The team used nested PCR amplification of a signature segment of the borrelial 16S ribosomal RNA gene for detection and direct DNA sequencing of the PCR amplicon for molecular validation.

They found DNA evidence of an unknown Borrelia spirochete in an archived blood sample of a patient diagnosed with and treated for neurologic Lyme disease. The results were published in the International Journal of Molecular Sciences.

“The gateway to new DNA sequencing tests is proper polymerase chain reaction (PCR), and we have designed a pair of genus-specific PCR primers to detect all pathogenic spirochetes, including Borrelia burgdorferi, Borrelia miyamotoi and other related borreliae in this group and to prepare the templates for direct DNA sequencing,” said Sin Hang Lee, MD, a Milford Hospital pathologist and lead author of the paper.

The pathologists concluded that a sensitive and reliable DNA-based test is needed to support the diagnosis of Lyme disease and Lyme disease-like borreliosis.

While the research did not use the xxpress qPCR thermal cycler, the machine’s speed and reliability gives it potential for fast turnaround studies and testing to understand more about disease and treatment.