Staining Techniques in Microbiology

Bacteria are colourless and nearly invisible under the light microscope because their refractive index is close to that of the surrounding medium. Stains add contrast, reveal morphology, and, in many cases, give an immediate provisional diagnosis from a clinical specimen — which is exactly why examiners love linking stain results to vignettes, specimen types, and organisms. A stain is a salt with a chromophore (co…