IN-VITRO CONVERSION OF BORRELIA-BURGDORFERI TO CYSTIC FORMS IN SPINAL-FLUID, AND TRANSFORMATION TO MOBILE SPIROCHETES BY INCUBATION IN BSK-H MEDIUM

The purpose of this study was to examine the structural alterations of Borrelia burgdorferi when exposed to spinal fluid. Normal, mobile spi rochetes were inoculated into spinal fluid, and the spirochetes were c onverted to cysts (spheroplast L-forms) after 1-24 h. When these cysti c forms were transferred to a rich BSK-H medium, the cysts were conver ted back to normal, mobile spirochetes after incubation for 9 to 17 da ys. The cultures were examined by dark field microscopy (DFM), interfe rence contrast microscopy (ICM) and transmission electron microscopy ( TEM). When neuroborreliosis is suspected, it is necessary to realize t hat B, burgdorferi can be present in a cystic form, and these cysts ha ve to be recognized by microscopy. This study may also explain why cul tivation of spinal fluid often is negative with respect to B. burgdorf eri.