Which Vibrio species is associated with shellfish such as oysters and can cause explosive watery diarrhea and bullae formation?

• A. Pseudomonas aeruginosa
• B. Vibrio parahaemolyticus
• C. Vibrio vulnificus
• D. Vibrio cholerae

Answer: (C)

Shellfish exposure, especially oysters, points to a Vibrio infection, but the distinguishing feature here is the development of rapid, bullous skin lesions along with severe disease after seafood exposure. Vibrio vulnificus is a coastal, halophilic bacterium that can contaminate raw shellfish and cause explosive watery diarrhea. More notably, it can invade through skin or sepsis, producing painful, rapidly spreading cellulitis with bullae and can lead to necrotizing fasciitis and septicemia, especially in people with liver disease or weakened immunity. This combination of oyster-related exposure and bullae formation is characteristic of Vibrio vulnificus. Other Vibrio species cause seafood-related gastroenteritis (like V. parahaemolyticus) or cholera-like diarrhea (V. cholerae) but do not typically produce bullae, and Pseudomonas aeruginosa is unrelated in this context.