Isolation of spirochetes from the skin of patients with erythema chronicum migrans in Austria.

Spirochetal organisms were isolated from biopsies (skin punches) of the erythematous anular skin lesion of three patients with erythema chronicum migrans. The organisms were cultivated in modified Kelly's medium and - after an incubation period of 2 weeks - discovered by dark field microscopy (X 200). Compared with the Lyme disease agent Borrelia burgdorferi the organisms did not differ in shape, motility and reaction with polyclonal antiserum. Differences to B. burgdorferi were found in (i) very slow growth of the isolated organisms in modified Kelly's medium and in (ii) non reactivity with monoclonal antibodies against the outer membrane protein of B. burgdorferi. It is concluded that the Austrian isolates are closely related to but not identical with the Lyme disease agent.