Pulmonary infection by Rhodococcus equi presenting with positive Ziehl-Neelsen stain in a patient with human immunodeficiency virus: a case report

INTRODUCTION Patients with human immunodeficiency virus carry a significant risk of contracting opportunistic infections. The worldwide increased incidence of tuberculosis has instituted pulmonary tuberculosis as an important diagnostic consideration in patients with human immunodeficiency virus presenting with lower respiratory tract infection. A positive result on the readily-available Ziehl-Neelsen stain usually leads to the initiation of antituberculous treatment, since tuberculosis may exert a rapid and even fatal clinical progress in human immunodeficiency virus coinfection. However, a number of other acid-fast bacteria might be implicated as offending pathogens. This case highlights the importance of broadening the list of pathogens that can account for a positive Ziehl-Neelsen stain in this select group of patients. CASE PRESENTATION We describe the case of a 34-year-old, Albanian man with untreated human immunodeficiency virus, presenting with clinical and radiologic signs of pulmonary tuberculosis and a positive Ziehl-Neelsen sputum specimen, who was finally diagnosed with pulmonary infection by Rhodococcus equi. CONCLUSIONS Rhodococcus equi is a rare cause of pulmonary disease, even in patients with human immunodeficiency virus, and a positive Ziehl-Neelsen sputum specimen often misleads clinicians to more common organisms such as mycobacteria. A high index of suspicion, broadening the spectrum of optional pathogens, and effective communication between clinicians and microbiologists can ensure an efficient diagnostic and therapeutic approach.