Capnocytophaga canimorsus, a potential emerging microorganism in splenectomized patients

A 48-year-old splenectomized patient who had recent dog exposure was admitted with respiratory failure. The peripheral blood film was reviewed and showed the presence of bacteria within the neutrophils (note their characteristic filamentous rod-shape morphology). Blood culture and further sequencing of DNA confirmed the microorganism as Capnocytophaga canimorsus, part of the normal flora found within the oral cavity of dogs and cats. Subsequent to the diagnosis, the patient developed septic shock and disseminated intravascular coagulation, despite intravenous antibiotics administration, and died within a few days of commencing treatment. This case illustrates the importance of urgent screening of peripheral blood films for bacteria, especially in septic asplenic patients who have a history of domestic animal exposure. In addition, this group of patients should be given oral penicillin for prophylaxis.