December 2, 2022

In hopes of ‘eradicating’ Lyme disease, doctor bait mice with antibiotics


Kim Lewis believes we may see an end to Lyme disease in the not-so-distant future.

“There are only a handful of diseases that can be eradicated,” he said. “I think Lyme is really ready for eradication.”

Lewis, is a professor of biology at Northeastern University and director of that university’s Antimicrobial Discovery Center, which he says “should explain what I do for a living.”

Next summer, Lewis and his colleagues will drop antibiotic-laden mouse baits into the woods of Massachusetts, hoping to stop transmission of the disease at its source.

Lewis discovered – or rediscovered – a compound, forgotten since the 1950s, that he believes could be a game-changer in the treatment of Lyme disease and possibly take a major step in eliminating the disease.

“Mice are the primary host and transmitter,” he said. “If you can get rid of the disease in mice, you basically break the chain of transmission, and that could very well eradicate the disease. “

The syndrome was first identified by researchers at Yale University in the 1970s, found in Lyme and East Lyme patients. The disease has since spread widely.

Of the 3,320 ticks tested by the state in 2020, 28.8% were found to be carriers of Lyme disease.

There have been more than 27,500 cases of Lyme disease identified among Connecticut residents in the 11 years between 2009 and 2019, the most recent data available.

According to data from the state’s Department of Public Health, cases of Lyme disease are reported every month of the year, although there are peaks every year during the summer months, usually in July.

Most of the time Lyme disease is treated with broad-spectrum antibiotics like doxycycline, Lewis said, “And they work great.”

“For the majority of patients, you are given a course of antibiotics for two to three weeks and you are rid of the infection,” he said.

But broad-spectrum antibiotics have drawbacks. Their use leads to increased resistance to antibiotics, which Lewis said was “a huge problem,” and they kill both harmful and helpful bacteria in the body.

Lewis and his team therefore went looking, literally, for a more specific drug. “We decided it would be a good idea to define an antibiotic that selectively kills Borrelia burgdorferi,” Lewis said.

They found a compound in soil samples that specifically attacks spirochetes, a type of bacteria like Lyme and syphilis, which “are quite different from other bacteria,” Lewis said. “From their name it follows that they have a spiral shape, and they turn into things that make them particularly mean.”

He found it, hygromycin, which he believed to be new but which was originally discovered in 1953. It has been largely abandoned, he said, because it does not have wide application.

“What our analysis showed is that the hygromycin is quite weak against virtually all of the bacteria we tested, except the spirochetes,” Lewis said. “It is terribly potent against spirochetes, all of the spirochetes that we have tested, including Borrelia burgdorferi.”

Lewis’s research now takes place on two tracks. They are studying the use of hygromycin as a treatment in humans, but it will take time. They are several trials away from seeking FDA approval.

They also throw mousetraps in the Massachusetts wilderness. Mice are at the heart of the spread of Lyme disease, believed to be the primary vectors, acting as reservoirs of the disease. The ticks that spread Lyme disease feed on white-legged mice, so if you can cure the mice, you may be able to cure the disease.

Lewis said he and his colleagues “are preparing to set up bait next year in the wild,” each bait inoculated with hygromycin. “I actually have a grant from NIH to try out exactly this proposition.”

Although he is excited about the prospect of a new, more specific treatment for Lyme disease, Lewis said it was still a long way off.

“If we start now, if all goes well, in two years we will start clinical trials,” he said.

But this will still only treat one patient at a time. Baiting mousetraps with an antibiotic that specifically targets Lyme disease has the potential, Lewis said, to protect future generations.

“I think it’s pretty realistic to get rid of Lyme,” Lewis said.

About a decade ago, the Centers for Disease Control and Prevention attempted a similar strategy with doxycycline, and it worked, Lewis said, to some extent. Doxycycline is more difficult to increase to this level and could cause problems with antibiotic resistance if used.

“It is impractical to spread doxycycline in the United States. It is an important last resort antibiotic for some pathogens,” he said. “You need something that’s going to be selective. And can you imagine spreading broad spectrum antibiotics over large areas? It invites unbridled resistance.