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Vibrio vulnificus Empirical Treatment — SCE Infectious Diseases MCQ

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ModerateTropical & Imported InfectionsVibrio vulnificus Empirical TreatmentSCE Infectious Diseases

A 40-year-old man with alcoholic liver disease presents with rapidly progressive necrotising cellulitis of the left leg with haemorrhagic bullae after cutting his leg on a barnacle-covered surface while fishing in warm coastal waters in the Gulf of Mexico. He is septic. What is the critical empirical antibiotic combination?

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Correct answer: E — IV Doxycycline 100 mg BD plus IV Ceftriaxone 2 g daily — covering Vibrio vulnificus

Necrotising cellulitis with haemorrhagic bullae after saltwater/shellfish exposure in a patient with liver disease is classic for Vibrio vulnificus until proven otherwise. Empirical treatment MUST include Doxycycline (which covers Vibrio) plus a 3rd-generation cephalosporin (Ceftriaxone or Cefotaxime) for synergistic bactericidal activity. Standard skin/soft tissue regimens (Flucloxacillin) do not cover Vibrio. Urgent surgical debridement is usually required in addition. Mortality exceeds 50% with delayed treatment.

Reference: UKHSA 2023 – Vibrio infections; CDC 2024 – Vibrio vulnificus