Ultrastructural differences among spirochetes isolated from patients with Lyme disease and related disorders, and from Ixodes ricinus.

Previous studies on cells of strains B31 isolated in the U.S.A. from Ixodes dammini and strain G25 isolated in Sweden from Ixodes ricinus, showed that their ultrastructure was similar, but not identical. For this reason the studies were extended to spirochetes isolated directly from patients with Lyme disease and related disorders. Included in the present study were three strains isolated from skin, blood and spinal fluid, respectively, from patients with Lyme disease, two strains from patients with erythema chronicum migrans and one strain from a patient with acrodermatitis chronica atrophicans. Three additional strains isolated in Sweden from Ixodes ricinus were also studied. All spirochetes were examined after negative straining with 1% ammonium molybdate. The cells of each individual strain were identical except for one strain isolated from a tick. This isolate was found to consist of two morphologically different spirochetes. Comparison of morphological features of cells from various isolates revealed certain differences. The cells of the different strains could be divided into at least four groups for which cell size and shape as well as number of flagella varied. By morphological criteria, all cells were found to belong to the genus Borrelia.