Hello! What is the best histological stain or immunostaining marker to visualize bacteria in sections of animal tissues? Optimally, staining all (or most) bacteria but no eukaryotic cells, and working at least for cryosections.
You can easily visualize most bacteria within paraffin embedded tissue sections with either a Brown and Brenn (Gram) stain or Warthin-Starry silver stain and either will give you good morphology at higher magnification. As mentioned above, FISH probes are available at the general bacteria level (EUB 388) and also for many bacteria at the genus and/or species level and provide a superior means to visualize the bacteria in situ.
I suggest Modified technique of Brown & Hopp to visualize bacteria in tissue sections, The procedure is described in a textbook of histopathological techniques by Bancroft..
"Theory and practice of histological techniques" by Bancroft and Gamble give good information on staining bacteria in paraffin sections. Try the modified Brown - Brenn method to stain GRam positive / Gram negative organisms, Zeil-Neelsen for Mycobacterium, or Warthin -Starry for spirochetes ( this one is a little tricky to do).
Same protocols will work on cryosections though I would advise cutting them a little thicker ~ 5 microns and use superfrost plus ( adhesive slides).
If you do not want the other cells staining leave out the counterstain but this could make orientation difficult and may look unusual in photographs.