Infective Endocarditis by Capnocytophaga Species-A Narrative Review

Bacteria belonging to the genus Capnocytophaga are thin, capnophilic, Gram-negative bacilli with tapered ends that include nine species that are isolated from the mouth of humans and animals and, from a phylogenetical perspective, they belong to the family Flavobacteriaceae. Two more species, namely C. endodontalis and C. stomatis have been recovered from a periapical abscess and human and animal infections, respectively. Capnocytophaga spp. can cause serious and potentially life-threatening infections in humans, such as bacteremia and meningitis, most commonly in the context of penetrating trauma as a result of contact with animals, especially after animal bites. Other invasive diseases such as osteomyelitis, septic arthritis, and infective endocarditis (IE) may also occur more rarely. The aim of this study was to review all previously described cases of IE by Capnocytophaga spp. and provide information about the epidemiology, microbiology, antimicrobial susceptibility, clinical characteristics, treatment, and outcomes of this infection. A narrative review based on a search in PubMed, the Cochrane Library, and Scopus was performed. Studies published until 11 September 2023 providing relevant data for IE caused by Capnocytophaga spp. in humans were included. A total of 31 studies containing data from 31 patients were included. A history of dog bites was present in 10 out of 26 patients (38.5%). A prosthetic valve was present in 3 patients (9.7%). The most commonly infected valve was the aortic valve, followed by the tricuspid valve. Fever, embolic phenomena, paravalvular abscess, and sepsis were the most common clinical presentations. Beta-lactams and aminoglycosides were the antimicrobials most commonly used. Surgery was performed in 20 patients (64.5%). Overall mortality reached 16.1%.