New Drug To Treat Tick Bites Symptoms

By Meredith Cohn

The Baltimore Sun

About 300,000 people a year are infected with Lyme disease through tick bites, and for up to 20 percent of them the condition persists after a course of antibiotics. But just in time for tick season, Johns Hopkins University researchers are now onto a promising treatment for those sufferers.

It would be the first specific treatment for those who contend with such symptoms as fatigue, muscle and joint aches, and brain fog, sometimes severe. It also would be a major step for researchers who long struggled to even prove those symptoms were related to Lyme — partly because Lyme bacteria was no longer detected in blood tests after the initial treatment.

Most cases of Lyme disease are resolved with a course of doxycycline, amoxicillin or cefuroxime, for two to four weeks.

Researchers have tried mixing the drugs to treat the as many as one in five patients with persistent cases. However, mixing two of the drugs has failed to knock out all cases.

Now researchers from the Hopkins Bloomberg School of Public Health have had success in mice with a three-drug combination — daptomycin, doxycycline and ceftriaxone — to treat what is now called post-treatment Lyme disease syndrome. The new study was published in the March 28 journal Discovery Medicine.

The idea is that there is slow-growing variant of Lyme bacteria, Borrelia burgdorferi, which persists and causes these sometimes severe arthritis-like symptoms. The “persister” bacteria were found to be immune to the standard single-antibiotic treatment.

Researchers believe certain conditions cause these bacteria to switch from their normal fast-growth mode to variants with little or no growth.

Past studies also have suggested these variants can be killed with the right drugs.

The next step for the three-drug combination will be testing it in people.

“There is a lot of excitement in the field, because we now have not only a plausible explanation but also a potential solution for patients who suffer from persistent Lyme disease symptoms despite standard single-antibiotic treatment,” said Dr. Ying Zhang, the study’s senior author and a professor in the Bloomberg School’s department of molecular microbiology and immunology.

Zhang said the idea of drug combinations may translate to treatments for other infectious diseases caused by such persister bacteria.

meredith.cohn@baltsun.com

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