PetriKey

Bacterium

Clostridium tetani

Terminal-spore tetanus rod

klos-TRID-ee-um TET-uh-nye

Gram positivegram-positiverodanaerobespore-formingtoxinneurotoxin

High-yield clue

Terminal spores give a tennis-racket or drumstick shape, and tetanospasmin blocks release of inhibitory GABA and glycine to cause spastic paralysis.

Overview

An obligate anaerobic, spore-forming Gram-positive rod that produces the neurotoxin tetanospasmin. It is the standard teaching organism for spastic (rigid) paralysis after wound contamination.

Classification

  • Gram-positive
  • Rod
  • Obligate anaerobe
  • Spore-forming (terminal endospore)

Lab & identification clues

  • Terminal spore 'tennis-racket' appearance
  • Obligate anaerobe
  • Motile study distinction
  • Toxin-mediated disease vocabulary

Associations

  • Puncture wound / soil contamination
  • Lockjaw (trismus) and risus sardonicus presentation vocabulary
  • Spastic paralysis and opisthotonus

Commonly confused with

  • Clostridium botulinum
  • Clostridium perfringens

Your notes

Original student-study summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment, dosing, or specimen-handling guidance.

OpenStax: Microbiology 2e organism classification foundationssourceNCBI Bookshelf: Medical Microbiology organism chapterssourceCDC: CDC disease and public-health topic pagessource