Rhodococcus equi as a cause of pneumonia in the acquired immunodeficiency syndrome

Abstract

Rhodococcus equi is an emergent microorganism associated to opportunistic infections in immune-compromised individuals, especially in patients infected with the human immunodeficiency virus. A search was carried out in the Virtual Library of Infomed; 215 scientific works were reviewed without limits of publication years and countries. From them, 55 were chosen.  Rhodococcus equi is an intracellular pathogen that is able to grow and live inside the macrophages   expressing the Mac-1 (CD11b/CC18) receptor in the surface and destroying them later. The most common clinical manifestation is insidious beginning pneumonia, tending to cavitation in its natural evolution. The diagnosis is made through identification in culture of affected tissues samples. Blood cultures are positive in 50 % of the immune-depressed people. At the radiographic diagnosis, the most common findings referred to in the scientific literature are lobar compromise and cavitation. The particular evolution of the patients with acquired immune-deficiency syndrome and pneumonia due to Rhodococcus equi forces the implementation of therapeutic schemes based on antimicrobials with intracellular bactericide activity, administered firstly intravenously and during a long time, and even to perform the surgery. Rhodococcus equi infection is an infrequent complication in patients with acquired immunodeficiency syndrome, but having a high lethality rate, therefore it should be suspected   in patients presenting a respiratory infection of unusual curse.  The precocious diagnosis, combined and prolonged antimicrobial treatment and early beginning of the highly active antiretroviral therapy could improve the evolution and prognosis of these patients.