Next-Generation DNA Sequencing the New Face of Brain Infection Diagnosis

A new proof-of-principle study from John Hopkins University School of Medicine has successfully used next generation DNA sequencing to diagnose or rule out suspected brain infection.

The study, published in the journal Neurology, suggests that rapid analysis of the huge amounts of genetic and biological information using a computer could be the new face of cost-effective diagnostic tool.

"By incorporating modern genetic sequencing techniques into pathology diagnostics, we were able to investigate the potential presence of infection in 10 subjects and found appropriate explanations of clinical problems in eight out of 10 patient cases examined in this study," said Carlos Pardo-Villamizar, M.D., associate professor of neurology at the Johns Hopkins University School of Medicine, in a statement.

For the study, researchers enrolled 10 patients at The John Hopkins Hospital who have clinical signs of brain infection and rapid onset of neurological symptoms including weakness in the extremities, partial paralysis numbness, headaches or seizures.

The researchers conducted a biopsy of the brain lesion of each patient. They then sequenced the DNA of the brain tissue they have acquired using commercially available genetic sequencing technologies, which can read millions of pieces of DNA simultaneously.

Using a database of human and non-human DNA sequences containing 2,817 bacterial genomes, 4,383 viral genomes and 26 single-cell pathogen genomes, the researchers subtracted out the human DNA results and ranked the top three other species found in the sample that were thought to be a potential infectious organisms.

With this method, the researchers successfully identified the cause of infection for three of the participants. On the other hand, the method did not point out the pathogen causing the infection in five participants. Instead, the negative findings helped the clinicians to have a better understanding over the disease being experienced by the patients.

However, the new diagnostic method for brain infection has one major drawback. It solely depends on the available genetic sequences of pathogens. This means that more research is needed to construct a baseline of what organisms may be found in normal, healthy brain. There is also a need to expand the current database of human and non-human DNA sequences.