Three cases of severe pharyngitis were reported in a community of immigrants. The patients had thick pharyngeal exudates, neck swelling, and difficulty swallowing. One of them died from severe heart failure. The toxin responsible has a mechanism of action most similar to another toxin produced by which of the following bacteria?

Question

Three cases of severe pharyngitis were reported in a community of immigrants.  The patients had thick pharyngeal exudates, neck swelling, and difficulty swallowing.  One of them died from severe heart failure.  The toxin responsible has a mechanism of action most similar to another toxin produced by which of the following bacteria?

Quizplus · Accepted Answer

Severe pharyngitis with exudates and cervical lymphadenopathy in a group of people with unknown vaccination status should raise suspicion for respiratory diphtheria infection. Diphtheria toxin can cause severe myocarditis and heart failure, which occurred in one of the patients in the vignette. Diphtheria toxin acts in a similar manner to exotoxin A, which is produced by Pseudomonas aeruginosa. P aeruginosa produces several extracellular products, including exotoxin A, collagenase, elastase, fibrinolysin, phospholipase C, and DNAse. These substances assist in its invasion and dissemination in human tissues. Although they are structurally different, both diphtheria toxin and exotoxin A ribosylate and inactivate elongation factor-2 (EF-2), halting human cell protein synthesis and causing cell death. Exotoxin A is a major virulence factor and is responsible for the high mortality associated with P aeruginosa septicemia. 11ec160b_3822_d192_9249_c16dff64256c_MD0001_00 Educational objective: Diphtheria toxin and pseudomonal exotoxin A act by ribosylating and inactivating elongation factor-2, inhibiting host cell protein synthesis and causing cell death.

Three Cases of Severe Pharyngitis Were Reported in a Community