Infective endocarditis caused by Capnocytophaga canimorsus; a case report

The dog, valves' best friend: infective endocarditis due to Capnocytophaga canimorsus-a case report

Background

Capnocytophaga canimorsus is a Gram-negative bacillus found in the oral microbiota of dogs. It is a very rare cause of endocarditis. We hereby present a case of aortic valve endocarditis due to this microorganism.

Case Summary

A 39-year-old male was admitted to hospital with a history of intermittent fever and exertion dyspnoea and showed signs of heart failure on physical examination. Transthoracic and transoesophageal echocardiography confirmed the presence of a vegetation in the non-coronary cusp of the aortic valve, aortic root pseudoaneurysm, and left ventricle-to-right atrium fistula (Gerbode defect). The patient underwent aortic valve replacement with a biological prosthesis. The fistula was closed with a pericardial patch, although a dehiscence of the patch was detected in post-operative echocardiogram. The post-operative period was complicated by acute mediastinitis and cardiac tamponade secondary to a pericardial abscess, requiring emergent surgery. The patient made a good recovery afterwards and was discharged 2 weeks later.

Discussion

Capnocytophaga canimorsus is a very rare cause of endocarditis, although it can be very aggressive, with high degree of valve damage, necessity of surgery, and high mortality. It mainly affects young men with no previous structural heart disease. Due to its slow growth, blood cultures can be negative, so other microbiological techniques such as 16S RNA sequencing or matrix-assisted laser desorption/ionization and time-of-flight (MALDI-TOF) can be helpful for diagnosis.

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.

An Infected Bicuspid Aortic Valve, an Anomalous Coronary Artery, and a Dog-Bitten Postman

Risk factors for infective endocarditis (IE) include congenital heart defects, poor dentition, immunosuppression, or recent instrumentation. The occupational hazard of a dog bite, combined with bicuspid aortic valve (BAV) led to IE. 16S ribosomal DNA was able to pinpoint the causative organism. A healthy 33-year-old postman presented in profound heart failure and sepsis due to aortic regurgitation and an aortic root abscess. He underwent emergency aortic valve replacement and was found to have a BAV and anomalous right coronary artery. Blood cultures remained negative. 16S ribosomal DNA polymerase chain reaction (PCR) revealed the causative organism was Capnocytophaga canimorsus. On review, he recalled receiving a dog bite followed by a febrile illness a few days later. Congenital BAVs may become infected by seemingly innocuous injuries. 16S rDNA PCR is a more sensitive and specific diagnostic test than culture. This case demonstrates its utility in providing appropriate antimicrobial management for IE.

Double valve infective endocarditis due to Capnocytophaga canimorsus

Infective endocarditis caused by Capnocytophaga canimorsus, a commensal organism commonly found in dog saliva, is uncommon. We describe a case of a 76-year-old male with native aortic and mitral valve endocarditis with ventricular-atrial fistulization due to Capnocytophaga canimorsus. He was successfully treated with intravenous antimicrobials and surgery. Capnocytophaga canimorsus should be considered as a cause of infective endocarditis in patients with negative blood cultures, in asplenic patients, and in those with appropriate exposures.

Capnocytophaga canimorsus and infective endocarditis-making a dog's dinner of the aortic valve: a case report

Background

Capnocytophaga canimorsus, a bacterium found in the oral cavities of healthy cats and dogs, is rarely reported as a cause of infective endocarditis. In this report we describe such a case in a young, male dog owner who presented acutely unwell in heart failure.

Case summary

A 47-year-old male presented with a subacute onset of fever, night sweats, weight loss, dyspnoea, and peripheral oedema. On clinical examination typical features of infective endocarditis, heart failure, and aortic regurgitation were found. The patient had no conventional risk factors for infective endocarditis but was a dog owner. Transthoracic echocardiography revealed vegetations on the right coronary and non-coronary cusps of the aortic valve causing severe eccentric aortic regurgitation and left ventricular dilatation. Initial blood cultures taken prior to the initiation of antimicrobial therapy showed no growth. The patient underwent aortic valve and root replacement and a 16S ribosomal RNA polymerase chain reaction (16S rRNA PCR) of the resected aortic valve tissue, using the additional primer set 785F/1175R targeting the V5–7 region of 16S rRNA, identified C. canimorsus. The patient was treated post-operatively with a 6-week course of meropenem and made a good recovery.

Discussion

Suspicion of C. canimorsus causing infective endocarditis should be considered in culture-negative infective endocarditis in individuals who have close contact with dogs or cats. Those who are immunocompetent can be susceptible to this infection and so this diagnosis should not be disregarded in healthy individuals. A 16S rRNA PCR can help identify this bacterium and should be used early in cases of culture-negative infective endocarditis.

A case of Capnocytophaga canimorsus endocarditis in a non-immunosuppressed host: the value of 16S PCR for diagnosis

Capnocytophaga canimorsus is a rare cause of endocarditis and is particularly unusual in non-immunosuppressed hosts. It is associated with animal bites, particularly those from dogs. This case describes a healthy 59-year-old woman, with no identifiable risk factors or dog bite history, who presented with fever of unknown origin. Echocardiography demonstrated an aortic valve mass and root abscess, in keeping with endocarditis, requiring urgent valve replacement surgery. Eight sets of blood cultures were drawn in total; after prolonged incubation, one set grew C. canimorusus. There was initial uncertainty over this being the causative organism, given the lack of immunosuppression or dog bite history, but 16S PCR of the valve identified the same organism, permitting targeted treatment. This case highlights the value of valve 16S PCR as a diagnostic tool in endocarditis.

A Bite So Bad: Septic Shock Due to Capnocytophaga Canimorsus Following a Dog Bite

Infection by Capnocytophaga canimorsus (C. canimorsus), a Gram-negative rod found in the normal oral flora of canine and feline species and transmitted through bites or scratches, is a rare phenomenon. Infections most commonly occur in alcoholics and immunocompromised patients. In this report, we describe the case of a middle-aged male with a history of alcohol abuse who presented with septic shock and multisystem organ failure following a suspected dog bite. The patient was a 59-year-old Caucasian male with alcohol abuse disorder who initially presented with encephalopathy and lethargy. The patient had scratches and multiple healing wounds, with a mottled appearance on his extremities. According to his wife, the patient had been playing aggressively with his dog at home. On admission, he was febrile, tachycardic, and saturating in the 80s on ambient air. His extremities rapidly developed diffuse purpura and dry gangrene of all digits along with the tip of his nose and genitals. The patient developed septic shock and multisystem organ failure. Blood cultures initially grew Gram-positive cocci and Gram-negative rods for which broad-spectrum antibiotics were initiated. Follow-up blood cultures were positive for C. canimorsus and the antibiotic regimen was adjusted accordingly. His condition continued to deteriorate. His family opted for comfort measures only and he died soon after. Common sequelae of C. canimorsus infection include septic shock with multisystem organ failure, disseminated purpuric lesions, hypotension, encephalopathy, and acute renal failure. As seen in our patient, C. canimorsus infection should be considered in such patients, particularly if there is a recent history of an animal bite. Prompt initiation of appropriate treatment is essential to improve patient prognosis.

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.