Capnocytophaga canimorsus: a rare case of conservatively treated prosthetic valve endocarditis

The Great pretender: the first case of septic shock due to Capnocytophaga canimorsus in Sardinia. A Case report and review of the literature

Capnocytophaga canimorsus (C. canimorsus) is an emerging pathogen in critical care. C. canimorsus is a Gram-negative bacillus, commonly isolated as a commensal microorganism of the oral flora of healthy dogs and cats. A 63-year-old woman came to the emergency department with fever, chills, and malaise 2 days after a minor dog bite. After admission to the medicine ward, she developed respiratory failure and livedo reticularis. In the intensive care unit (ICU), she presented full-blown septic shock with thrombocytopenia, coagulopathy, severe acute kidney injury, and liver injury. We describe the first case of septic shock with Multiple Organ Dysfunction Syndrome related to Capnocytophaga canimorsus infection in Sardinia and its treatment in a tertiary hospital ICU. We also review recent literature on the relevance of C. canimorsus in human disease and critical illness.

Capnocytophaga tricuspid valve endocarditis: a case report and literature review

Capnocytophaga canimorsus is a Gram-negative zoonotic pathogen capable of causing serious infection following dog or cat bite. Infections often manifest as sepsis, fatal septic shock, gangrene, bacteraemia, meningitis and endocarditis. Here we report a case of C. canimorsus bacteraemia complicated by tricuspid valve infective endocarditis and septic pulmonary emboli.

Capnocytophaga canimorsus tricuspid valve endocarditis

Capnocytophaga canimorsus is an uncommon cause of infective endocarditis (IE) and mainly affects persons with compromised immune-systems who have been in contact with dogs. We describe a case of C. canimorsus tricuspid valve IE in a 70 year-old dog-owner where diagnosis and treatment were delayed. The reason for the delayed diagnosis in this case was likely due to that initial blood cultures were negative due to preceding antibiotic treatment, discrepancies between echocardiographic investigations, and a thymoma and colonic polyps which were thought to explain the symptoms. A multi-diciplinary approach in cases with suspected IE might help to avoid diagnostic delays.

Capnocytophaga canimorsus - a potent pathogen in immunocompetent humans - systematic review and retrospective observational study of case reports

Purpose: Severe and fatal Capnocytophaga canimorsus infection has been described in immunocompromised patients. Data of C. canimorsus infection in immunocompetent and risk factors of severe courses are missing. Our aims were to describe the epidemiology of C. canimorsus infection and to identify potential risk factors of sepsis and fatal outcome.Methods: Observational study and systematic review of all cases reported in immunocompetent subjects between 2002 and 2019.Results: A total of 128 cases of C. canimorsus infection in immunocompetent individuals were reported. Male gender comprised 74.2%, the median age was 58 years and 47.7% were admitted with sepsis. Case-fatality rate was 29.7% and especially high in septic patients (55.7%). Transmission by bite (OR = 2.37, 95% CI: 1.05-6.52) and incubation time ≤3 d (OR = 7.98; 95% CI: 2.33-27.34) were identified as risk factors of sepsis on admission, and early wound cleansing as protective (OR = 0.42; 95% CI: 0.14-0.96). Sepsis (OR = 23.67; 95% CI: 2.85-197.89) and septic shock (OR = 45.50; 95% CI: 3.08-676.55) were risk factors of fatal outcome, whereas early wound cleansing (OR = 0.05; 95% CI: 0.01-0.72), initial penicillin therapy with beta-lactamase inhibitors (OR = 0.48; 95% CI: 0.16-0.92) and surgical removal of infectious focus (OR = 0.38; 95% CI: 0.06-0.95) were protective factors.Conclusions: Immunocompetent patients with C. canimorsus infection frequently develop sepsis. A shorter incubation period in cases of sepsis might be related to higher infectious dose. Fatal outcome may be prevented by early wound cleansing, initial use of penicillins in combination with beta-lactamase inhibitors and surgical removal of an infectious focus.

Infective endocarditis caused by Capnocytophaga canimorsus; a case report

Background

Capnocytophaga canimorsus is a gram-negative bacterium and an oral commensal in dogs and cats, but occasionally causes serious infections in humans. Septicemia is one of the most fulminant forms, but diagnosis of C. canimorsus infection is often difficult mainly because of its very slow growth. C. canimorsus infective endocarditis (IE) is rare and is poorly understood. Since quite a few strains produce β-lactamase, antimicrobial susceptibility is pivotal information for adequate treatment. We herein report a case with C. canimorsus IE and the results of drug susceptibility test.

Case presentation

A 46-year-old man had a dog bite in his left hand 3 months previously. The patient was referred to our hospital for fever (body temperature > 38 °C), visual disturbance, and dyspnea. Echocardiography showed aortic valve regurgitation and vegetation on the leaflets. IE was diagnosed, and we initially administered cefazolin and gentamycin assuming frequently encountered microorganisms and the patient underwent aortic valve replacement. C. canimorsus was detected in the aortic valve lesion and blood cultures. It was also identified by 16S ribosome DNA sequencing. Ceftriaxone were started and continued because disk diffusion test revealed the isolate was negative for β-lactamase and this case had cerebral symptoms. The patient successfully completed antibiotic treatment following surgery.

Conclusions

We diagnosed C. canimorsus sepsis and IE by extended-period blood cultures and 16S ribosome DNA sequencing by polymerase chain reaction, and successfully identified its drug susceptibility.