The etiological agent that is rod-shaped, anaerobic and causes food intoxication is

The etiological agent that is rod-shaped, anaerobic and causes food intoxication is

• A. Clostridium botulinum
• B. Staphylococcus aureus
• C. Listeria monocytogenes
• D. Clostridium perfringens

Answer: (D)

Food intoxication means illness caused by a toxin that is already present in the food, before ingestion. The organism that best fits this is a rod-shaped anaerobe capable of producing a toxin in food, leading to rapid illness. Clostridium botulinum is a rod-shaped, anaerobic, spore-forming bacterium that can grow in anaerobic, improperly processed foods (like improperly canned products) and produce botulinum toxin preformed in the food. Ingesting that toxin instead of the bacteria itself causes the characteristic, often rapid, neurotoxic illness of botulism. The other options don’t fit as cleanly. Staphylococcus aureus is not rod-shaped, and while it can cause rapid food poisoning via preformed toxins, it’s excluded here by shape. Listeria monocytogenes is a rod-shaped bacterium but is a facultative anaerobe and typically causes disease through infection, not preformed toxin in food. Clostridium perfringens is a rod-shaped anaerobe that can cause food poisoning, but the illness is usually due to an enterotoxin produced in the gut after ingestion (a foodborne infection rather than toxin present in the food), which is a different mechanism from a true food intoxication.

Food intoxication means illness caused by a toxin that is already present in the food, before ingestion. The organism that best fits this is a rod-shaped anaerobe capable of producing a toxin in food, leading to rapid illness. Clostridium botulinum is a rod-shaped, anaerobic, spore-forming bacterium that can grow in anaerobic, improperly processed foods (like improperly canned products) and produce botulinum toxin preformed in the food. Ingesting that toxin instead of the bacteria itself causes the characteristic, often rapid, neurotoxic illness of botulism.

The other options don’t fit as cleanly. Staphylococcus aureus is not rod-shaped, and while it can cause rapid food poisoning via preformed toxins, it’s excluded here by shape. Listeria monocytogenes is a rod-shaped bacterium but is a facultative anaerobe and typically causes disease through infection, not preformed toxin in food. Clostridium perfringens is a rod-shaped anaerobe that can cause food poisoning, but the illness is usually due to an enterotoxin produced in the gut after ingestion (a foodborne infection rather than toxin present in the food), which is a different mechanism from a true food intoxication.