A 54-year-old diabetic patient complaints of an unresolved skin lesion on his foot. The lesion began several weeks ago as a blister and has since become a painful, erosive, expanding sore. On examination, the affected site is now 5 cm in diameter, with a black necrotic center and raised red edges. Which toxin has a mechanism of action most similar to the toxin responsible for tissue damage in this patient?
Anthrax toxin
Botulinum toxin
Cholera toxin
Diphtheria toxin
This is the history of ecthyma gangrenosum (skin infection) due to Pseudomonas aeruginosa. Exotoxin A of P. aeruginosa has a same mechanism of action as diphtheria toxin. Pseudomonas aeruginosa is a gram-negative bacterium, motile by polar flagella. It is catalase and oxidase test positive. It produces two impoant pigments: fluorecein and pyocyanin. Selective medium used for its isolation is ceimide agar.