A laboratory examines a smear from a wound suspected of tetanus. Which morphological feature is characteristic of Clostridium tetani?

• A Subterminal oval spores giving a tennis racket appearance
• B Non-sporing rods arranged in Chinese letter pattern
• C Central spores with a bamboo stick appearance
• D Round terminal spores giving a drumstick appearance ✓

Explanation

Clostridium tetani forms spherical terminal spores that bulge the end of the rod, producing the classic drumstick appearance. The tennis racket description applies to subterminal sporing clostridia such as some strains of C. perfringens variants, and central spores are typical of C. bifermentans. The Chinese letter arrangement describes Corynebacterium diphtheriae due to snapping division. C. tetani is a strict anaerobe, motile by peritrichous flagella, and swarms on agar plates.

Reference: Ananthanarayan and Paniker's Textbook of Microbiology, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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