South Middlesex Times

A genetic analysis of Lyme disease bacteria may pave the way for improved diagnosis, treatment, and prevention of the tick-borne ailment.

By mapping the complete genetic makeup of 47 strains of Lyme disease-causing bacteria from around the world, an international team has created a resource for identifying specific bacterial strains that infect patients. Researchers said this could enable more accurate diagnostic tests and treatments tailored to the exact type or types of bacteria causing each patient’s illness.

"This comprehensive, high-quality sequencing investigation of Lyme disease and related bacteria provides the foundation to propel the field forward,” said Steven Schutzer, a Rutgers New Jersey Medical School professor and coauthor of the study published in mBio. “Every modern research project — from clinical to public health to ecology and evolution to bacterial physiology to medical-tool development to host-bacteria interaction — will benefit from this work."

Researchers said the genetic information uncovered in this study — which explains how the bacteria evolve and spread and which genes are essential for survival — may help scientists develop more effective vaccines against Lyme disease.

Lyme disease is the most common tick-borne illness in North America and Europe, affecting hundreds of thousands of people annually. The disease arises from bacteria belonging to the Borrelia burgdorferi sensu lato group, which infect humans through the bite of infected ticks. Symptoms can include fever, headache, fatigue, and a characteristic skin rash. If left untreated, the infection can spread to joints, the heart, and the nervous system, causing more severe complications.

Case numbers are increasing steadily, with 476,000 new cases each year in the US alone. These numbers may grow faster with climate change, according to study authors.

The research team sequenced complete genomes representing all 23 known species in this group. Most had not been sequenced before this effort. The National Institutes of Health-funded project included multiple strains commonly associated with human infections as well as species not previously known to cause disease in humans.

By comparing these genomes, researchers reconstructed the evolutionary history of Lyme disease bacteria back millions of years. They discovered that these bacteria likely originated before Pangea's breakup, explaining their current worldwide distribution.

The study also revealed how these bacteria exchange genetic material within and between species through recombination. This process allows rapid evolution and adaptation to new environments. Researchers identified specific hotspots in bacterial genomes where genetic exchange occurs frequently involving genes that help interact with tick vectors and animal hosts.

"By understanding how these bacteria evolve and exchange genetic material, we're better equipped to predict and respond to changes in their behavior," said Weigang Qiu, a professor at City University of New York and senior author of the study.

To facilitate ongoing research, web-based software tools (BorreliaBase.org) were developed allowing scientists to compare Borrelia genomes and identify determinants for human infection capability.

Looking ahead, researchers plan further analysis on more strains from understudied regions. They also aim to investigate functions unique to disease-causing strains' genes which could reveal new therapeutic targets.

As factors like climate change expand Lyme disease's geographic range, this research provides valuable tools for combating this rising public health threat.

“This is a seminal study,” said Benjamin Luft from Stony Brook University’s Renaissance School of Medicine. “It provides researchers with data going forward better tailoring treatment against all causes of Lyme disease.”

Other contributors among 20 authors include Claire Fraser and Emmanuel Mongodin from University Maryland School Medicine; Sherwood Casjens from University Utah School Medicine; supported by Steven & Alexandra Cohen Foundation.

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