Cardiobacterium Hominis Subacute Endocarditis

1University of Wisconsinn, Madison, WI
2University of Wisconsin, Madison, WI

Meeting: Hospital Medicine 2014, March 24-27, Las Vegas, Nev.

Abstract number: 656

Case Presentation:

, A 21 year‐old Caucasian man with no significant past medical history was referred for night sweats and fatigue. The patient denied foreign travel, sick contacts, dental appointments and risky sexual encounters. Physical examination revealed a young man with with stable vital signs with a loud blowing systolic murmur heard best at cardiac apex.Laboratory investigations demonstrated microcytic anemia with an ESR 67 mm/hr. CT chest abdomen and pelvis was reviewed from the outside hospital demonstrated splenomegaly (18 cm) with a geographic somewhat wedge‐shaped infarct. Transthoracic echocardiogram (TTE) suggested a fistulous connection with the thoracic aorta which prompted a cardiac magentic resonance imaging (MRI) which demonstrated that the posterior leaflet of the mitral valve was hypoplastic and the septal leaflet was thickened and enlarged, likely congenital with moderate mitral regurgitation with regurgitant jet identified along the posterior wall of the left atrium, No fistulous communication was identified between the left atrium and descending thoracic aorta and delayed mid myocardial gadolinium enhancement in the inferoseptal wall the left ventricle and posterior wall of the right ventricle towards apex is consistent with fibrosis likely from prior myocarditis. Blood cultures 2/2 turned positive at 52.8 hours with gram negative rods. The patient was started on IV Cefriaxone 2 gm daily. X ray orthopantogram showed no dental pathology or periapical abscess. Nine days after admission Cardiobacterium hominis was identified as the pathogen. The patient was discharged home after 11 days in hospital and continued therapy with intravenous antibiotics to complete a six week course with follow up with infectious disease.


Cardiobacterium hominis is a slow‐growing Gram‐negative bacillus of the HACEK group (Haemophilus parainfluenzae, Haemophilus aphrophilus, Haemophilus paraphrophilus, Actinobacillus actino‐mycetemcomitans, C. hominis, Eikenella corrodens, and Kingella species). C. hominis is a member of the normal flora of the nose and throat in most 70% individuals . Rheumatic and congenital heart disease, poor dentition, and recent dental or surgical work are commonly noted risk factors for C.hominis endocarditis; but usually no entry portal can be found, as was the case in our patient. The presentation is typically subacute with symptoms lasting for a few weeks to months. A longer duration of symptoms has been reported to occur with C. hominis endocarditis when compared with endocarditis caused by other HACEK organisms. Because of its fastidious and slow‐growing nature with an average duration of 6 days in published cases, recommendations have been to hold blood cultures for 10–14 days and our case confirms this recommendation as the cultures were reported after 9 days. The prognosis of both native valve and prosthetic valve C. hominis endocarditis is favorable. C. hominis is almost always susceptible to penicillin. However, because of reports of beta‐lactamase producing C. hominis strains causing endocarditis, American Heart Association recommends using third generation cephalosporin. Treatment duration is 4 weeks for native valve endocarditis and 6 weeks for prosthetic valve endocarditis.


Clinicians must have high degree of suspicion for C.hominis endocarditis as early diagnosis and antibiotics can result in favorable outcome. Prolonged cultures often reveal this diagnosis.

To cite this abstract:

Turagam M, Nautiyal A. Cardiobacterium Hominis Subacute Endocarditis. Abstract published at Hospital Medicine 2014, March 24-27, Las Vegas, Nev. Abstract 656. Journal of Hospital Medicine. 2014; 9 (suppl 2). Accessed April 8, 2020.

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