Puncture wounds are at risk for infection with which organism that causes tetanus (lockjaw)?

• A. Clostridium botulinum
• B. Staphylococcus aureus
• C. Clostridium tetani
• D. Streptococcus pyogenes

Answer: (C)

Puncture wounds create a low-oxygen environment that favors growth of anaerobic, spore-forming bacteria like Clostridium tetani. This organism produces tetanospasmin, a toxin that blocks inhibitory neurotransmitters in the spinal cord, leading to unrelenting muscle contractions and the characteristic lockjaw of tetanus. So the organism responsible for tetanus is Clostridium tetani. The other organisms listed cause different conditions—Clostridium botulinum produces botulinum toxin with flaccid paralysis from contaminated foods, Staphylococcus aureus typically causes skin and soft tissue infections, and Streptococcus pyogenes also drives skin/soft tissue infections and other diseases—not tetanus. Vaccination against tetanus and proper wound care reduce risk.