The reliability of various in vitro techniques to identify Borrelia burgdorferi infection is still unsatisfactory. Using a high-power resolution videomicroscope and staining with the borrelia genus-specific monoclonal flagellar antibody H9724, we identified borrelial structures in skin biopsies of erythema chronicum migrans (from which borrelia later was cultured), of acrodermatitis chronica atrophicans, and of morphea. In addition to typical borreliae, we noted stained structures of varying shapes identical to borreliae found in a “borrelia-injected skin” model; identical to agar-embedded borreliae; and identical to cultured borreliae following exposure to hyperimmune sera and/or antibiotics. We conclude that the H9724-reactive structures represent various forms of B. burgdorferi rather than staining artifacts. These “atypical” forms of B. burgdorferi may represent in vivo morphologic variants of this bacterium.
From the Department of Dermatology, Division of Immunology, Allergy, and Infectious Diseases (E.A., C.P.) and of General Dermatology (H.K., W.J.), University of Vienna, Vienna, Austria; and Department of Pathology (A.K.), University of Freiburg, Freiburg, Germany.
Address correspondence and reprint requests to Dr. E. Aberer at Department of Dermatology, University of Graz Medical School, Auenbrugger Platz 8, A-8036 Graz, Austria.
These data were presented as a video at the fifth international conference on Lyme Borreliosis, 1992, Arlington, Virginia. That video, “Borrelia burgdorferi in the skin: a morphological and immunohistochemical study of the heterogenous appearance of this microorganism,” has been prepared simultaneously and will be made commercially available to interested scientists.