A rare case of Actinomyces israelii presenting as pericarditis in a 75-year-old man.

Actinomyces israelii is a gram-positive bacillus that is rarely associated with infections in the general population. A. israelii belongs to the normal flora of the body and it rarely becomes pathogenic. Cardiac involvement is rare and in most cases involves the pericardium. Fewer than 20 cases of pericardial actinomycosis have been reported in the literature since 1950. We report the case of a 75-year-old man with a history of coronary artery disease with recent myocardial infarction and stent placement, atrial fibrillation, and recent colonic perforation with subsequent colectomy/colostomy who presented to our hospital with a 2-week history of left-sided chest pain. Workup revealed the presence of a pericardial effusion and pericarditis. Pericardial fluid analysis demonstrated A. israelii. An examination and discussion of the literature is performed regarding this rare manifestation of human actinomycosis.