ABSTRACT
Cardiobacterium hominis is a small, catalase-negative, oxidase-positive, pleomorphic gram-negative coccobacillus, which is a member of the HACEK group of microorga nisms (Haemophilus species, Actinobacillus actinomycetemcomicans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae).1,2 The microorganism is a part of the normal human nasal and oropharyngeal ³ora, but upon disturbance of the mucosal integrity it can become invasive and pathogenic.1,3 Although it is present in the oral cavity of almost 70% of healthy individuals, it has also been detected in stool samples and genitourinary specimens by ³uorescent antibody analysis.4,5 The bacterium was Šrst isolated in four patients with infective endocarditis in 1962.6 At that time, it was classiŠed as a Pasteurella-like organism and was designed group II ID. Slotnick and Dougherty subsequently proposed the name Cardiobacterium hominis in 1964.7 Until 2004, C. hominis was the sole Cardiobacterium species known to cause human infections. In 2004, however, Han et al. identiŠed a new Cardiobacterium species from a patient with endocarditis complicated by ruptured cerebral aneurysm; the new isolate called Cardiobacterium valvarum.8
