Sepsis and Meningitis Due to Capnocytophaga cynodegmi after Splenectomy

Sir—Severe Capnocytophaga canimorsus infections occur in immunocompromised patients; most notably, after splenectomy [1, 2]. Although Capnocyophaga cynodegmi animal-bite wound infection has been described, it has been characterized as a more benign infection that is restricted to skin and soft tissues. We report the first case, to our knowledge, of C. cynodegmi sepsis and meningitis resulting in death in a splenectomized woman who received a dog bite. A 72-year-old woman with diabetes mellitus and a history of traumatic splenectomy was bitten on her left hand by her pet dog 24 h before she presented to the emergency department with fever (temperature, 39°C), chills, and headache. Initial laboratory studies showed a WBC count of 8.9 cells/mm3, with 21% bands. A CT scan of the head revealed no abnormality. The patient's mental status declined, and CSF studies revealed a WBC count of 24 cells/mm3, with 73% neutrophils; a glucose level of 69 mg/dL; and a protein level of 127 mg/dL. The patient's condition deteriorated rapidly in the next several hours; facial purpura and a progressive macular rash developed over her entire body. Gram stain of a CSF sample revealed gram-negative rods. Despite treatment with ceftriaxone, the patient developed coagulopathy, metabolic acidosis, and hypotension consistent with septic shock. She died within 24 h after admission and ∼48 h after the initial dog bite. Cultures of blood and CSF yielded a gram-negative rod preliminarily identified as a Capnocytophaga species. Further identification in Department of Microbiology at East Tennessee State University (Johnson City, TN) revealed a filamentous gram-negative bacterium that required a CO2-enriched environment for growth. The organism tested positive for oxidase, catalase, and nitrate and was a weak fermenter. It grew on 5% sheep blood agar and chocolate agar but not on MacConkey agar. It was not motile and tested negative for hydrolysis of urease, citrate, and esculin. This combination of characteristics identified the isolate as C. cynodegmi, since C. canimorsus is nitrate negative and the other Capnocyophaga species are negative for both oxidase and catalase [3]. Capnocytophaga was first isolated in 1976 from blood and CSF of a patient who had received a dog bite [4]. Brenner and colleagues [5] discovered that both C. canimorsus and C. cynodegmi cause human infection, often by way of dog or cat bites or scratches. They also noted that C. cynodegmi was usually associated with localized wound infection, whereas C. canimorsus was more frequently isolated from patients with septicemia. We would now suggest that C. cynodegmi may not always be limited to soft-tissue infections. Sarma and Mohanty [1] previously reported a case of cellulitis, bacteremia, and pneumonitis caused by C. cynodegmi in a diabetic man after he received a dog bite. Our patient presented with purpura fulminans and clinical signs of sepsis and died in a matter of hours; this presentation is very similar to those described for patients with C. canimorsus infection. To our knowledge, this is the first case of C. cynodegmi infection presenting as sepsis and meningitis in an immunocompromised host, and it serves as a reminder that different species may have a spectrum of virulence determinants that may emerge in the right clinical circumstances. Potential conflicts of interest All authors: no conflicts.