Capnocytophaga canimorsus sepsis: two clinical cases at the Bolzano Regional Hospital

Capnocytophaga canimorsus is a commensal bacterium in the oral cavity of dogs and cats and has been isolated from humans with a history of dog or cat bites or scratches. C. canimorsus are capnophilic facultative anaerobic, fastidious gram negative fusiform rods, included in the CDC group DF-2 or dysgonic fermenter 2. The bacterium can cause severe illness in patients at elevated risk i.e. after splenectomy, with alcohol addiction, chronic lung or liver diseases or immunosuppression. In 2010 at the Bolzano Regional Hospital (Northern-Italy) C. canimorsus was isolated from blood cultures in two splenectomised patients suffering from septicaemia.The bacterium is difficult to cultivate because of its specific requirements for nutrients as well as to identify with routine automated instruments; therefore we used molecular typing by 16S rDNA sequencing.The true number of C. canimorsus infections is probably underestimated due to the fastidious growth of the organism. However, given the severity of the disease and the poor outcome one should consider this bacterium to apply appropriate diagnostic methods for this etiologic agent.