A throat swab from a child with a grayish pseudomembrane is stained with Albert stain. The slide shows green bacilli with bluish-black metachromatic granules. What is the primary stain used in this technique?
- A Carbol fuchsin
- B Crystal violet
- C Toluidine blue and malachite green ✓
- D Safranin
Correct answer: C. Toluidine blue and malachite green
Explanation
Albert stain uses toluidine blue and malachite green as the primary stain. The metachromatic granules of Corynebacterium diphtheriae stain bluish-black, while the rest of the bacillus stains green. Carbol fuchsin is for ZN stain, crystal violet for Gram stain, and safranin is a counterstain.
Reference: Ananthanarayan and Panicker's Textbook of Microbiology, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.