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Capnocytophaga Asplenic Sepsis — SCE Infectious Diseases MCQ

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HardInfection Prevention & ControlCapnocytophaga Asplenic SepsisSCE Infectious Diseases

A 60-year-old man with a history of splenectomy develops overwhelming post-splenectomy infection. Despite aggressive resuscitation and antibiotics, he dies within 18 hours. Post-mortem blood cultures grow Capnocytophaga canimorsus. He was bitten by his pet dog 2 days before admission. What is the significance of this organism?

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Correct answer: B — Capnocytophaga canimorsus is a commensal of canine/feline oral flora that causes fulminant sepsis specifically in asplenic, alcoholic, or immunocompromised patients — dog/cat bites in asplenic patients require immediate prophylactic antibiotics

Capnocytophaga canimorsus is a Gram-negative rod found in dog and cat saliva that causes fulminant sepsis with DIC, purpura fulminans, and multi-organ failure specifically in asplenic, alcoholic, or immunocompromised patients. Mortality is 25–30% even with treatment. In asplenic patients, any dog/cat bite or scratch should receive immediate empirical antibiotics (Co-amoxiclav — first-line for animal bites covers Capnocytophaga, Pasteurella, and anaerobes) and close clinical follow-up. Asplenic patients should be counselled about this risk at the time of splenectomy.

Reference: UKHSA 2024 – Green Book Ch 7: Asplenia; NICE NG149 2020 – Bite wounds