What is the correct match of causative organism to the type of toxin: Vibrio (Vibrio) cholerae, Shigella (Shigella) dysenteriae, Rotavirus, and Clostridium (Clostridium) botulinum to enterotoxin, cytotoxin, or neurotoxin?

Correct Organism-Toxin Matching

The correct answer is B) 1-d, 2-c, 3-b, 4-a: Vibrio cholerae produces enterotoxin, Shigella dysenteriae produces cytotoxin, Rotavirus produces enterotoxin, and Clostridium botulinum produces neurotoxin.

Detailed Organism-Toxin Relationships

1. Vibrio cholerae → Enterotoxin (d)

• Vibrio cholerae produces cholera toxin, which is definitively classified as an enterotoxin that causes fluid and electrolyte efflux resulting in diarrhea 1
• The cholera toxin is an oligomeric complex that binds to surface membranes, becomes internalized, and increases adenylate cyclase activity and cAMP, leading to massive fluid secretion 1
• This toxin acts directly on ion transport in intestinal epithelial cells through interaction with membrane receptors and second messenger systems 2

2. Shigella dysenteriae → Cytotoxin (c)

• Shigella dysenteriae produces Shiga toxin, which is primarily characterized as a cytotoxin that directly damages and kills cells 3
• The cytotoxic activity of Shiga toxin can be measured through HeLa cell assays, demonstrating its direct cell-killing properties 3, 4
• While Shiga toxin has multiple biological activities (enterotoxic, neurotoxic, and cytotoxic), the cytotoxic activity is its predominant and defining characteristic 3
• Research demonstrates that cytotoxin titers parallel toxin antigen levels, confirming cytotoxicity as the primary measurable activity 4

3. Rotavirus → Enterotoxin (b)

• Rotavirus produces viral proteins that function as enterotoxins, causing diarrhea through disruption of intestinal epithelial cell function
• The viral NSP4 protein acts as an enterotoxin by increasing intracellular calcium and disrupting tight junctions in intestinal cells

4. Clostridium botulinum → Neurotoxin (a)

• Clostridium botulinum produces botulinum toxin, which is definitively classified as a neurotoxin that blocks acetylcholine release at peripheral cholinergic nerve terminals 1
• Botulinum neurotoxins are the most potent biological neurotoxins known, causing descending flaccid paralysis through inhibition of acetylcholine transmission at the neuromuscular junction 1, 5
• The CDC explicitly describes botulinum toxin as a neurotoxin that produces cranial nerve palsies followed by descending symmetric flaccid paralysis 5
• Seven antigenically distinct botulinum neurotoxins (A-G) have been identified, all sharing the same neurotoxic mechanism of action 1

Key Clinical Distinctions

• Enterotoxins (Vibrio cholerae, Rotavirus) primarily affect intestinal fluid and electrolyte transport, causing secretory diarrhea without significant cell death 1, 2
• Cytotoxins (Shigella dysenteriae) directly kill cells, leading to tissue destruction and bloody diarrhea 3, 4
• Neurotoxins (Clostridium botulinum) block neurotransmitter release at nerve terminals, causing paralysis rather than gastrointestinal symptoms 1, 5