Corynebacterium Diphtheriae

Description

Corynebacterium diphtheriae is represented at the cellular scale as pleomorphic Gram-positive bacilli, ranging from straight to slightly curved rods with clubbed, rounded, and occasionally swollen poles. Cells commonly lie at oblique angles to one another, forming palisades and V or L shaped arrangements from snapping division, a coryneform pattern that helps distinguish corynebacteria from more uniformly cylindrical bacilli. Within the cytoplasm, metachromatic (volutin) granules may be suggested as polar inclusions, classically prominent on special stains. Scale is microscopic. That morphology matters when you are correlating a suspected diphtheria case with the first laboratory impressions from a throat swab. Club-shaped rods in angular groupings, paired with polar granules on Albert stain or methylene blue, push the differential toward toxigenic C. diphtheriae and away from streptococcal pharyngitis, while PCR or Elek testing confirms toxin production. Airway risk is immediate. Pseudomembrane formation, myocarditis, and neuropathy all trace back to diphtheria toxin, so the organism’s identification has direct implications for antitoxin administration, isolation, and contact prophylaxis. Use this artwork in microbiology and infectious disease teaching decks to reinforce coryneform morphology, metachromatic granules, and classic arrangements seen on smear preparation. It also fits clinical laboratory manuals, public health messaging, and textbook chapters on vaccine-preventable respiratory infections where visual differentiation from commensal diphtheroids is discussed. Anatomical accuracy verified by SciePro's Medical Advisory Board.