36 known species of Borrelia (12 of these species are known to cause Lyme disease or borreliosis and are transmitted by ticks).
Other tick-borne relapsing infections are acquired from other species, such as Borrelia hermsii or Borrelia parkeri or Borrelia miyamotoi, which can be spread from rodents, and serve as a reservoir for the infection, via a tick vector.
Important considerations: The choice of an agent should be based on local antimicrobial sensitivities, site of infection, cost, and comorbid conditions. Generally, the most common agents/regimens are listed first. Listed dosages may need to be adjusted for renal dysfunction.
Erythema migrans – Early disease: (Usual length of therapy: 2-3 weeks)
Ceftriaxone 2 grams IV q24h (range: 1-2 grams q12-24h) x 3-4 weeks – serious disease. Alternatively give Cefotaxime 2 grams IV q8h x 3-4 weeks.
Other: Generally, the oral regimens listed above will cover the most common areas of involvement such as the joints. Reserve IV therapy for severe cases or extensive disease. Length of therapy should be guided by close observation and overall clinical improvement of the patient. For patients unable to tolerate preferred regimens (allergies, pregnancy, etc.), consider Azithromycin 500mg orally once daily for adult patients.