Gram-negative anaerobic endocarditis: Two case reports and review of the literature

The rarity of anaerobic gram-negative endocarditis limits the ability of ph ysicians to define its prognosis. Two cases of endocarditis due to Bacteroi des fragilis are described, and a review of the English literature for all cases of anaerobic gram-negative endocarditis reported since 1940 is presen ted. The disease predominantly affects males. Clinical features are similar to those of endocarditis due to nonanaerobic organisms, but underlying hea rt disease is less common and the rate of thromboembolic complications is h igh. All deaths reported were due to Bacteroides spp.; no deaths due to Fus obacterium spp. have been reported. Treatment with metronidazole has dramat ically improved the prognosis of patients with endocarditis due to anaerobi c gram-negative bacilli.