Overview The spirochetes are spiral-shaped bacteria Includes ("BLT") Borrelia Leptospira Treponema Visualization only Borrelia can be visualized using light microscopy use Wright's or Giemsa stain (aniline dyes) Leptospira and Treponema are visualized by dark-field microscopy "Borrelia is BIG and can be seen with a light BULB"