Peripheral blood smear, Wright's stain. Microorganisms Bacteria appear on H and E as blue rods or cocci regardless of gram reaction. Colonies appear as fuzzy blue clusters. Tissue gram stains are all basically the same as that used in the microbiology lab except that neutral red is used instead of safranin. The most sensitive method for demonstrating them is Methenamine silver.
Spirochetes are very difficult to stain.
The best method is the Warthin-Starry. A Giemsa stain may help demonstrate donovan bodies and leishmania. Spirochetes with Warthin-Starry silver stain. This stain uses carbol-fuchsin to stain the lipid walls of acid fast organisms such as M. tuberculosis . The most commonly used method is the Ziehl-Neelsen method, though there is also a Kinyoun's method.