Isolation of Borrelia burgdorferi sensu lato from blood of patients with erythema migrans

Background: We assessed the isolation rate of Borrelia burgdorferi sensu La te from blood in European patients with typical erythema migrans and evalua ted the course and outcome of their illness. Patients and Methods: Adult patients diagnosed with erythema migrans and fr om whom borreliae cultured from blood were included in this study. Results: Borreliae were isolated from the blood of 35/2,828 (1.2%) patients , on average 7 days (range 1-47 days) after the appearance of erythema migr ans, Only seven (20%) patients reported constitutional symptoms, 24/35 isol ates were typed of which 20 were Borrelia afzelii and four were Borrelia ga rinii, 31 (88.6%) patients were treated with oral antibiotics while four (1 1.4%) received ceftriaxone iv, The course and outcome of the illness were f avorable in all patients. Conclusion: In European patients with erythema migrans the yield of blood c ulturing was Low, spirochetemia was often clinically silent and the course and outcome of the illness were favorable; the predominantly isolated strai n was B. afzelii.