Fungemia and Septic Arthritis Caused by Saprochaete capitata in a Patient with Fanconi Aplastic Anemia: A Case Report

Saprochaete capitata (formerly known as Blastoschizomyces capitatus, Trichosporon capitatum, Geotrichum capitatum) is a rare but emerging yeast-like fungus. It is commonly found in environmental sources and can be isolated from skin, gastrointestinal system and respiratory tract of healthy individuals as well. It mainly infects patients with hematological malignancies such as acute myeloid leukemia (AML), especially in the presence of neutropenia; and mortality rates are high in those patients. Although the data about the in vitro antifungal susceptibility are limited, it is being reported that amphotericin B and voriconazole are more effective on S.capitata isolates whereas caspofungin had no activity. Here, we report a case of fungemia and septic arthritis due to S.capitata in a patient with Fanconi aplastic anemia. A 22-year-old male patient with Fanconi aplastic anemia was hospitalized in our hematology department for bone marrow transplantation. Two days after the hospitalization, neutropenic fever developed and multiple nodules similar to candidiasis were detected in his liver with the whole abdomen magnetic resonance imaging (MRI). Caspofungin treatment (single 70 mg/kg loading dose, followed by 1 x 50 mg/kg/day) was started. The patient remained febrile, and his blood culture yielded S.capitata. The treatment regimen was changed to a combination of liposomal amphotericin B (3 mg/kg/day) and voriconazole (2 x 4 mg/kg/day). A few days later, pain and swelling came out on patient's left knee and he underwent a surgical process with the prediagnosis of septic arthritis. Culture of synovial fluid was also positive for S.capitata. On the 26th day of the hospitalization, the patient died due to sepsis and multiple organ failure. Patient's blood and synovial fluid samples were incubated in BacT/Alert automated blood culture system (bioMerieux, France). After receiving the growth signal, yeast cells were seen in Gram staining and cream-coloured, wrinkled, yeast-like colonies that were able to grow at 45 degrees C and resistant to cycloheximide were detected on Sabouraud dextrose agar (SDA). Urease test was negative, and according to API 20C AUX (bioMerieux, France) system, none of the carbonhydrates were utilized except glucose. The isolates that were able to produce annelloconidia in corn meal-Tween 80 agar slide culture were identified as S.capitata. The identification was further confirmed by DNA sequence analysis. Minimal inhibitory concentrations (MICs) of amphotericin B, fluconazole, voriconazole, and caspofungin were found to be 0.5 mu g/ml, 1.5 mu g/ml, 0.032 mu g/ml, and > 16 mu g/ml respectively. Repetitive sequence based PCR (rep-PCR) (DiversiLab system, bioMerieux, France) was used to determine clonal relatedness of the isolates from blood and synovial fluid samples. The isolates were indistinguishable (similarity coefficient > 97%) according to rep-PCR. In conclusion, S. capitata infections should be taken into consideration in the presence of fungemia and septic arthritis in hematological patients who receive caspofungin therapy.