Rhodococcus equi, previously called Corynebacterium equi, is known to cause pneumonia in foals and swine. Although it was known to cause infection rarely in humans, R equi infection in humans has increased with the advent of HIV and increased use of immunosuppressants.

We report a case of a 48-year-old male patient with newly diagnosed HIV/AIDS presenting with recurrent R equi bacteremia, pericardial effusion, and pericardial cyst. The infection was treated with drainage of the pericardial effusion and cyst and 2 weeks of intravenous vancomycin and 6 months of oral azithromycin and levofloxacin.

Rhodococcus equi causes pericarditis and pericardial effusion. It can be effectively treated with debridement, drainage, and a prolonged course of antibiotics. In vitro antibiotic susceptibility should be checked as resistance to antibiotics can develop, especially if drainage is inadequate.