Which characteristic applies to the toxin produced by C. diphtheriae
**Question:** Which characteristic applies to the toxin produced by C. diphtheriae
A. Inhibits neuromuscular transmission
B. Inhibits protein synthesis
C. Inhibits DNA replication
D. Induces respiratory distress
**Core Concept:** C. diphtheriae is a bacterium that produces a toxin responsible for the diphtheria disease. The toxin has a detrimental effect on cellular processes leading to the characteristic symptoms seen in diphtheria patients.
**Why the Correct Answer is Right:** The toxin produced by C. diphtheriae is a diphtheria toxin, which belongs to the family of bacterial exotoxins. This toxin has a specific mechanism of action that results in the characteristic symptoms seen in diphtheria patients. It is a protein that ADP-ribosylates the eukaryotic elongation factor 2 (EF-2), which in turn inhibits protein synthesis in eukaryotic cells.
**Why Each Wrong Option is Incorrect:**
A. Inhibiting neuromuscular transmission is incorrect because diphtheria toxin does not affect neuromuscular junctions. It directly targets the eukaryotic cells, impairing protein synthesis, not neuromuscular transmission.
B. Inhibiting protein synthesis is the correct answer (as explained above) and the reason why this option is wrong is that it does not specifically mention the toxin produced by C. diphtheriae.
C. Inhibiting DNA replication is incorrect because diphtheria toxin does not target DNA replication. Its action is on protein synthesis, as mentioned above.
D. Inducing respiratory distress is a symptom of diphtheria, but it is not a characteristic of the toxin itself. The toxin's mechanism of action is responsible for respiratory issues in patients.
**Clinical Pearl:** Diphtheria is a serious bacterial infection caused by C. diphtheriae that primarily affects the respiratory system. The toxin produced by the bacteria is responsible for the characteristic symptoms seen in the disease, including respiratory distress. Correct management of diphtheria involves administering specific antitoxin therapy to neutralize the toxin's effects.