Capnocytophaga canimorsus is a gram-negative rod that can be transmitted primarily by dog bites. This life-threatening organism commonly causes sepsis in patients with splenectomy or alcoholism. A 53-year-old rheumatoid arthritis male treated with methotrexate (MTX) for 5 years was admitted for a 4-day history of fever and dyspnea. He had been bitten on a finger by the family dog 4 days before onset. Laboratory tests revealed pancytopenia, acute renal failure, and evidence of disseminated intravascular coagulation, and he subsequently developed acute respiratory distress syndrome. Furthermore, blood cultures grew gram-negative bacilli and despite intensive treatment, he died 5 days after admission. Later, C. canimorsus was identified from his culture samples using a species-specific polymerase chain reaction. C. canimorsus infections should be considered in the differential diagnosis of sepsis for immunocompromised hosts following animal bites.
Tamura, S., Koyama, A., Yamashita, Y., Shiotani, C., Nakamoto, H., Nakamoto, C., … Fujimoto, T. (2017). Capnocytophaga canimorsus sepsis in a methotrexate-treated patient with rheumatoid arthritis. IDCases, 10, 18–21. https://doi.org/10.1016/j.idcr.2017.08.002