The best antibiotics to treat Borrelia miyamotoi?
Borrelia miyamotoi may be a disease you have never heard of. But the threat of this tick-borne illness is very real. First described in Japan in 1995, this emerging infectious disease is transmitted by the same blacklegged tick which carries the Lyme disease pathogen. In “Antimicrobial susceptibility of Borrelia miyamotoi,” researchers examine the effectiveness of several antibiotic regimes in the treatment of HTBRF.
by Daniel J. Cameron, MD MPH
In the United States, as many as 15.4% of the blacklegged ticks were found to be infected with B. miyamotoi, compared with up to 4% in Europe and Japan, according to Koetsveld from the Center for Experimental and Molecular Medicine, Academic Medical Center, Amsterdam, the Netherlands. 
Meanwhile, “Seroprevalence studies in New England suggest that B. miyamotoi infection may be as common as anaplasmosis and babesiosis,” write the authors of one study. The researchers randomly tested 250 individuals living in Manitoba, Canada and found that 10% were seropositive for B. miyamotoi. 
Although B. miyamotoi is characterized by relapsing fever, a case series published in the Annals of Internal Medicine reports that only 2 out of 50 patients infected with B. miyamotoi actually exhibited a relapsing fever. 
“Recurrent fever episodes have only been observed in 10% [of the cases] and spirochetemia is calculated to be low in patients infected with B. miyamotoi,” Koetsveld explains in Antimicrobial Agents Chemotherapy. 
Fever episodes last for three days and are accompanied by flu-like symptoms such as headache, chills, abdominal discomfort, arthralgia and myalgia.
So, how do we treat this difficult to diagnose condition?
Until now, there have been no treatment guidelines for B. miyamotoi and regimes have been empirically based on the treatment for Lyme disease. “The antimicrobial susceptibility of B. miyamotoi has not yet been elucidated, due to difficulties with cultivation of B. miyamotoi spirochetes in vitro,” according to Koetsveld.What is the best way to treat Borrelia miyamotoi? Click To Tweet
“In this study we describe, to our knowledge for the first time, in vitro susceptibility of B. miyamotoi to the most commonly used antibiotics” in the treatment of B. miyamotoi and Lyme borreliosis.
The study authors demonstrated that B. miyamotoi is susceptible to doxycycline, azithromycin, and ceftriaxone but resistant to amoxicillin in vitro. The next step would be to show whether these drugs work in patients.
Note: This article was originally published July 19, 2017. It has been updated with new content.
- Koetsveld J, Draga ROP, Wagemakers A, et al. In vitro susceptibility of the relapsing fever spirochete Borrelia miyamotoi to antimicrobial agents. Antimicrob Agents Chemother. 2017.
- Kadkhoda K, Dumouchel C, Brancato J, Gretchen A, Krause PJ. Human seroprevalence of Borrelia miyamotoi in Manitoba, Canada, in 2011-2014: a cross-sectional study. CMAJ Open. 2017;5(3):E690-E693.
- Molloy PJ, Telford Iii SR, Chowdri HR, Lepore TJ, Gugliotta JL, Weeks KE, Hewins ME, Goethert HK, Berardi VP: Borrelia miyamotoi Disease in the Northeastern United States: A Case Series. Ann Intern Med 2015.