A recent study has found that a slow-growing variant form of Lyme bacteria causes severe symptoms in a mouse model. This variant bacterial form may be behind the persistent symptoms seen in 10% to 20% of patients who are not cured with the current Lyme antibiotic treatment.
Lyme disease affects approximately 300,000 people in the U.S. every year. Typically, two-to-four-week treatment with either doxycycline, amoxicillin, or cefuroxime clears infection and resolves symptoms. However, some 10 to 20% of patients continue to suffer persistent symptoms, such as fatigue, muscle and joint aches, and brain fog, that can persist for six months or longer.
For many doctors, post-treatment Lyme disease syndrome is controversial, partly because studies in these patients usually fail to indicate that Borrelia bacteria can be cultured from their blood, particularly after treatment. But Borrelia are able to switch from normal fast-growth mode to variant forms such as “stationary phase,” where there is next to no growth.
By isolating slow-growth forms of Borrelia burgdorferi, the Lyme bacterium, the researchers discovered that they resisted standard antibiotic treatment in the test tube as well as in the mice. However, a combination of daptomycin, doxycycline and ceftriaxone eradicated the Lyme infection in the mice.
The scientists now hope to test the drug combination in people who suffer from post-treatment Lyme disease syndrome.
Source: Johns Hopkins Bloomberg School of Public Health, April 23, 2019