Purulent pericarditis is uncommon and is rarely caused by anaerobic ba
cteria. We describe a 58-year-old man with purulent pericarditis secon
dary to infection with bacteriodes fragilis; the most likely source fo
r the B. fragilis infection was subsequently found to be a ruptured ap
pendix. His pericarditis eventually resolved after drainage of purulen
t fluid and treatment with antibiotics directed against B. fragilis. W
e also review 29 cases of anaerobic pericarditis previously reported i
n the English-language literature (we excluded those cases due to acti
nomyces). In 17 cases only anaerobic bacteria were isolated, while in
13 anaerobes were isolated with a mixture of facultative and/or aerobi
c bacteria. The cases were secondary to a contiguous focus of infectio
n or occurred via hematogenous seeding. Treatment of both anaerobic pe
ricarditis and purulent pericarditis due to aerobic bacteria entails a
dequate drainage and appropriate antibiotic therapy, and in all cases
there should be a search for the source of the organism infecting the
pericardium.