Researchers' discovery may explain difficulty in treating Lyme disease

North­eastern Uni­ver­sity researchers have found that the bac­terium that causes Lyme dis­ease forms dor­mant per­sister cells, which are known to evade antibi­otics. This sig­nif­i­cant finding, they said, could help explain why it's so dif­fi­cult to treat the infec­tion in some patients.

"It hasn't been entirely clear why it's dif­fi­cult to treat the pathogen with antibi­otics since there has been no resis­tance reported for the causative agent of the dis­ease," explained Uni­ver­sity Dis­tin­guished Pro­fessor Kim Lewis, who led the North­eastern research team.

In other chronic infec­tions, Lewis' lab has tracked the resis­tance to antibi­otic therapy to the pres­ence of per­sister cells - which are drug-tolerant, dor­mant vari­ants of reg­ular cells. These per­sister cells are exactly what they've iden­ti­fied here in Bor­relia burgdor­feri, the bac­terium that causes Lyme disease.

The researchers have also reported two approaches - one of them quite promising - to erad­i­cate Lyme dis­ease, as well as poten­tially other nasty infections.

Lewis and his col­leagues pre­sented their find­ings in a paper pub­lished online last week in the journal Antimi­cro­bial Agents and Chemotherapy. He co-authored the paper with North­eastern doc­toral stu­dents Bijaya Sharma and Autumn Brown, both PhD'16; recent grad­uate Nicole Matluck, S'15, who received her Bach­elor of Sci­ence in Behav­ioral Neu­ro­science; and Linden T. Hu, a pro­fessor of mol­e­c­ular biology and micro­bi­ology at Tufts University.

The research was sup­ported by grants from the Lyme Research Alliance and the National Insti­tutes of Health.

Lyme disease is a bacterial infection transmitted by ticks. Lyme disease was first recognized in 1975, after researchers investigated why unusually large numbers of children were being diagnosed with juvenile rheumatoid arthritis in Lyme, Conn., and two neighboring towns.

The investigators discovered that most of the affected children lived near wooded areas likely to harbor ticks. They also found that the children's first symptoms typically started in the summer months coinciding with the height of the tick season.

Several of the patients reported having a peculiar skin rash just before developing arthritis symptoms, and many also recalled being bitten by a tick at the rash site.

Further investigations resulted in the discovery that tiny deer ticks infected with a spiral-shaped bacterium or spirochete (which was later named Borrelia burgdorferi) were responsible for the outbreak of arthritis in Lyme. Ordinary "wood ticks" and "dog ticks" do not carry the infection.

The ticks most commonly infected with B. burgdorferi usually feed and mate on deer during part of their life cycle. The recent growth of the deer population in the northeast and the building of suburban developments in rural areas where deer ticks are commonly found have probably contributed to the increasing number of people with the disease.