A patient with bacteraemia and possible endocarditis caused by a recently-discovered genomospecies of Capnocytophaga: Capnocytophaga genomospecies AHN8471: a case report

Here we describe a case of bacteraemia and possible endocarditis in a 64-year-old white British man caused by a newly identified genomospecies of Capnocytophaga in a patient subsequently diagnosed with metastatic adenocarcinoma of the oesophagus. The source of the bacteraemia was presumed to be from the patient's own oral flora.Our case further confirms the potential for Capnocytophaga to cause systemic infections, highlights the availability and need for identification of isolates to species level and re-emphasises the difficulty in diagnosing Capnocytophaga infections due to their slow growth in the laboratory.The members of the genus Capnocytophaga are a group of capnophilic, facultatively anaerobic, Gram-negative bacilli that inhabit the oropharyngeal cavity of both humans and animals [1]. Their association with human periodontitis has been well documented [2]. More seriously, they have been regularly reported to be the causative agents in unusual cases of septicaemia and endocarditis, with immunosuppressed, asplenic or alcoholic patients at particular risk [3]. They have also been more rarely implicated in a wide range of infections including meningitis, haemolytic uraemic syndrome, spontaneous bacterial peritonitis, septic arthritis, and hepatic and cerebral abscesses [4-9]. Dog or cat bites have been shown to be a particular risk factor for transmission of Capnocytophaga canimorsus, which has the potential to cause severe sepsis in humans. In the past, many authors have simply reported the infectious agent as Capnocytophaga sp., due to the difficulty of laboratory identification of individual species by morphological or biochemical means alone [5]. Molecular techniques now allow accurate speciation, with the use of Polymerase Chain Reaction-Restriction Fragment Length Polymorphism Analysis (PCR-RFLP). Identification to species level is desirable as it may indicate the likely source of the infection and guide subsequent investigation or treatment.Here we descr