BACKGROUND: Pulmonary infections are a major cause of mortality and morbidity in patients infected with human immunodeficiency virus (HIV) and can progress rapidly to respiratory failure and death without appropriate therapy. Herein, we present a rare case of an advanced HIV infection and Rhodoccocus equi (R. equi) pneumonia in a young male who had severe paradoxical immune reconstitution inflammatory syndrome (IRIS).

CASE REPORT: A 47-year-old nonsmoking Hispanic man with advanced HIV infection presented with severe acute necrotizing pneumonia secondary to R. equi. Although his initial response to antimicrobial therapy was optimal, he became symptomatic again in spite of continuation of antibiotics as he developed severe paradoxical IRIS 3 weeks after starting a new highly active anti-retroviral therapy (HAART).

CONCLUSIONS: The diagnosis of IRIS remains challenging because of the wide variations in the clinical presentation and etiologies. In spite of its rarity as an opportunistic pathogen, we recommend that R. equi, an intracellular pathogen, be included in the differential list of pathogens associated with IRIS.

Keywords: Acquired Immunodeficiency Syndrome, Immune Reconstitution Inflammatory Syndrome, Rhodococcus equi