Albert Stain (Diptheria Bacilli)

Albert’s stain is a rapid differential staining method used to identify Corynebacterium diphtheriae by demonstrating metachromatic (Babès–Ernst) granules. The granules show up as distinctive dark blue–purple inclusions at the cell poles against a contrasting background, providing a presumptive laboratory diagnosis of diphtheria from clinical specimens. Culture and toxin testing are required to confirm infection.

The classical stains used to demonstrate Corynebacterium diphtheriae are Loeffler’s methylene blue and Albert’s stain. They highlight metachromatic (Babès–Ernst) granules in the bacilli; Albert’s yields a green background with violet granules while Loeffler’s methylene blue accentuates the granules. Routine Gram staining shows pleomorphic gram‑positive rods but is less sensitive for these characteristic granules.

Albert staining is a differential, metachromatic staining technique used to visualize metachromatic (Babès‑Ernst) granules in bacteria like Corynebacterium diphtheriae. Its principle relies on metachromasi

Albert stain (and Loeffler’s methylene blue) is the special stain for Corynebacterium; it highlights characteristic metachromatic (Babès–Ernst) granules. Using Loeffler’s or Albert stain shows bipolar, intensely stained polar granules within club‑shaped, Gram‑positive bacilli, aiding identification of Corynebacterium diphtheriae. These quick stains are applied to smears from throat swabs or cultures.

The hallmark of diphtheria is a thick, gray-white pseudomembrane on the tonsils, pharynx, or nasal passages that bleeds if scraped. This tough membrane can obstruct the airway; local toxin causes mucosal necrosis and ulceration, while systemic diphtheria toxin may produce myocarditis and neuropathies. Cervical lymphadenopathy with a "bull neck" appearance often accompanies it.

Ziehl–Neelsen (acid-fast) stain uses heated carbol fuchsin to penetrate lipid-rich mycobacterial cell walls. After staining, acid-alcohol decolorizer removes dye from non–acid-fast organisms, while mycobacteria retain the red carbol fuchsin because mycolic acids resist decolorization. A counterstain (usually methylene blue or malachite green) colors non–acid-fast cells and background for contrast, allowing identification of red acid-fast bacilli.