Rhodococcus equi (R. equi) infection can present at various anatomical sites, most commonly as pulmonary disease, with symptoms that often mimic other conditions such as tuberculosis (TB). Immunocompromised individuals with occupational exposure to herbivores (e.g., horses) are the most vulnerable. This report describes a newly diagnosed human immunodeficiency virus (HIV) patient with AIDS and significant respiratory disease, with a diagnosis of TB and R. equi infection during hospitalization. A 41-year-old male rural worker from Guia Lopes, Mato Grosso do Sul, Brazil, with exposure to horses, presented with productive cough and hemoptysis, weight loss, night sweats, and dyspnea for five months. He was diagnosed with HIV/AIDS (CD4 T cells: 11 cells/mm³; viral load: 37,600 copies/mL) and referred to a referral hospital. On admission, he had anemia and left lung cavitation with bronchiectasis and consolidation. Molecular rapid test for TB (TRM-TB) was negative; however, acid-fast bacilli (AFB) in sputum and urinary LF-LAM test were positive, and RIPE regimen (rifampicin, isoniazid, pyrazinamide, and ethambutol) for TB was initiated. Due to suspected alcoholic cirrhosis based on altered liver enzymes, portal and splenic vein dilatation, ascites, and lifestyle, an alternative TB regimen with levofloxacin, amikacin, and ethambutol was chosen. Subsequently, sputum microscopy revealed structures suggestive of R. equi, which was also isolated from blood culture and lung tissue culture. Lung histopathology showed granulomatous inflammation. These findings supported treatment of R. equi with meropenem and azithromycin. The patient improved hemodynamically, fever resolved, and he was transferred to a long-term care facility to complete treatment, with planned outpatient follow-up and molecular confirmation of the agent. Due to the scarcity of R. equi infection cases, it is essential to understand its clinical presentation, epidemiology, and diagnostic aspects for early institution of appropriate therapy, especially in immunocompromised patients, to mitigate the risk of unfavorable outcomes.
Rebouças et al. (2026) studied this question.