Direct staining is characterized by which statement?

Direct staining is characterized by which statement?

• A. It stains only the background
• B. It stains the bacteria
• C. It stains neither bacteria nor background
• D. It stains both bacteria and background equally

Answer: (B)

Direct staining uses basic dyes with a positive charge to color the bacteria. Bacterial cell surfaces are negatively charged, so the dye binds to the cells and leaves the background relatively clear. That’s why direct staining is described as staining the bacteria. The other statements describe staining the background, staining neither, or staining both equally, which don’t fit how this technique works.

Direct staining uses basic dyes with a positive charge to color the bacteria. Bacterial cell surfaces are negatively charged, so the dye binds to the cells and leaves the background relatively clear. That’s why direct staining is described as staining the bacteria. The other statements describe staining the background, staining neither, or staining both equally, which don’t fit how this technique works.