This case report is a case history of a femoral prosthesis infection caused by Rhodotorula mucilaginosa in a human immunodeficiency virus patient. Though the pathogenicity of this organism for bone tissue has been previously reported, this is the first reported case of an orthopedic prosthesis infection by this species of the genus Rhodotorula.
CASE REPORTA 41-year-old female human immunodeficiency virus patient sustained a fracture of the left femoral epiphysis in a road traffic accident in 1996. Surgical internal fixation was done but was followed by an outbreak of chronic coxitis (confirmed by magnetic resonance) until a femoral prosthesis was finally inserted in 2006. During 2007, an acute infection of the implanted prosthesis was diagnosed, with the patient suffering from a fever (38.5°C), strong local pain, and tumefaction. Furthermore, a fistula developed from the internal site of the prosthetic infection as far as the skin of the femoral region, with continuous pus discharge from its external opening. No overt signs of septicemia were observed, and mild leukocytosis was documented, whereas CD4 and CD8 levels were found to be normal. After receiving a 10-day course of intramuscular piperacillin, empirically, followed by no clinical improvement, the patient was admitted to the hospital. Magnetic resonance and bone scintigraphy documented the prosthesis infection. Also, drainage from the fistula was cultured. Particularly, it was plated onto sheep blood agar, mannitol salt agar, MacConkey agar, and Sabouraud dextrose agar (plates were provided by bioMérieux, Marcy l'Etoile, France). Blood culture plates were incubated at 36°C in air, anaerobically, and under 5% CO 2 -enriched atmosphere. Mannitol and MacConkey media were processed at 36°C under aerobic conditions. Finally, two Sabouraud plates were incubated at 36°C and 25°C, respectively, both in ambient air. After 24 h of incubation, neither bacterial nor fungal growth was observed, whereas Sabouraud cultures processed at 25°C yielded about 150 colonies of Rhodotorula mucilaginosa, as a single organism, after 48 h of incubation. Cultures from all of the other mentioned media remained negative, so that no aerobic, anaerobic, or microaerophilic organisms other than Rhodotorula were observed. Identification of the isolate was suggested by the phenotype of colonies, which were typically pink-red and smooth, and by microscopic features (round-shaped yeast cells without hyphae) and confirmed by the Vitek2 system (YST card; bioMérieux) and by the mini API system (ID32C gallery; bioMérieux). Gram staining of the secretion was carried out and documented the presence of numerous images of phagocytosis by polymorphonuclear leukocytes against yeast-like cells (the yeast-like cells were mostly observed inside the cytoplasm of granulocytes), indicating acute infection caused by yeast-like organisms. Low MICs were observed for amphotericin B and flucytosine against the isolate studied (MICs, 0.25 g/ml and Յ0.03 g/ml, respectively), whereas higher values were documented ...