Donor-Derived Transmission of Cryptococcus gattii sensu lato in Kidney Transplant Recipients

We describe cases of donor-derived transmission of Cryptococcus deuterogattii in 2 kidney transplant recipients in Brazil and published information on other cases. Prompt reduction of immunosuppression and initiation of antifungal therapy was required to successfully control the fungal infections and preserve engraftment.

A fter antiretroviral therapy for HIV patients was introduced, solid organ transplant recipients became one of the major risk groups for developing cryptococcosis, possibly transmitted from donors (1,2). We describe 2 cases of donor-derived transmission of Cryptococcus deuterogattii in Brazil. The donor in both of these cases was a 43-year-old man with an antemortem history of an unspecified brain tumor who had been declared brain dead after respiratory arrest.
Case-patient 1 was a 51-year-old man who received a kidney from the donor. Physicians initiated induction therapy with antithymocyte globulin and maintenance therapy with tacrolimus, prednisone, and azathioprine. On day 7 after the procedure, doctors performed a kidney biopsy after the patient experienced delayed graft function. Histopathology of the graft showed organisms consistent with Cryptococcus yeast cells, suggesting fungal pyelonephritis. The patient had no respiratory or neurologic complaints. Results from his laboratory tests showed 7,000 leukocytes/mm 3 , 201,000 platelets/µL, serum creatinine 13.29 mg/dL, and serum urea 132 mg/dL. Brain and thorax radiographs revealed no abnormalities. Results of a lumbar puncture showed an opening pressure of 18 cm H 2 O, 2 leukocytes/mm 3 , protein 63 mg/dL, and glucose 77 mg/dL; a Cryptococcus antigen latex (CrAg-latex) agglutination test result was positive (titer 1:8). Blood and urine cultures indicated Cryptococcus species, and the serum CrAg-latex agglutination test result was positive (titer 1:1,024).
After the diagnosis of cryptococcosis in the first patient, a 59-year-old woman (case-patient 2) who had received a kidney from the same donor was contacted for evaluation. Physicians had initiated induction therapy with antithymocyte globulin and maintenance therapy with tacrolimus, prednisone, and mycophenolic acid. She was discharged on day 8 after the procedure and was asymptomatic when recalled on day 10. Clinicians performed blood and urine cultures, radiographs of the chest and the brain, and a lumbar puncture. The radiograph revealed no abnormalities. Results of lumbar puncture showed opening pressure of 15 cm H 2 O, 3 leukocytes/mm 3 , protein 35 mg/dL, and glucose 174 mg/ dL. Results of India ink and CrAg-latex agglutination tests were positive (titer: 1:64). Blood cultures and a urine sample indicated Cryptococcus species. No fungal growth was detected in a cerebrospinal fluid sample. The serum CrAg-latex agglutination was positive (titer 1:1,024).
A revised histology of the brain biopsy of the donor showed yeasts of Cryptococcus species that had not been detected previously. Results of a CrAg-latex agglutination test performed on a stored serum sample from the donor was positive (titer: 1:1,024). To rule out infection by Cryptococcus species in the organ recipients prior to the transplantations, CrAglatex agglutination tests were performed on stored pretransplant serum samples from both recipients; results for both were negative.
Both patients were treated with amphotericin B lipid complex (5 mg/kg 1×/d for 21 d) in combination with 5-fluorocytosine (25 mg/kg 4×/d for 14 d); dosages of immunosuppressive drugs were lowered. Therapy was switched to intravenous fluconazole (400 mg/d) after results of blood and urine cultures became negative. After clinical and microbiological remission of the infection, dosage was adjusted on the basis of renal function to 300 mg/d of oral fluconazole and was maintained for 2 years. Three years after stopping all antifungal therapy, no relapse of cryptococcosis was documented.
We describe cases of donor-derived transmission of Cryptococcus deuterogattii in 2 kidney transplant recipients in Brazil and published information on other cases. Prompt reduction of immunosuppression and initiation of antifungal therapy was required to successfully control the fungal infections and preserve engraftment. All 6 isolates from the recipients were characterized at a reference laboratory at Universidade Federal de São Paulo (São Paulo, Brazil) and sent to Canisius-Wilhelmina Hospital (Nijmegen, The Netherlands). We performed AFLP (amplified fragment length polymorphism) fingerprinting and multilocus sequencing typing, which showed that all isolates were C. deuterogattii genotype AFLP6/VGII. The revision of slides from formalin-fixed paraffin-embedded tissue blocks from donor brain biopsies showed Cryptococcus yeasts. We performed fungal DNA extraction and amplified parts of CAP59, GPD1, IGS1, LAC1, PLB1, SOD1, and URA5 loci (2). Phylogenetic analysis showed genetic similarity between the C. deuterogattii isolates from the kidney recipients and those from the donor's brain (Figure).
On the basis of the 2 cases we describe and data from the literature review, we suggest the following procedures for effective clinical management: performing blood and urine cultures, radiograph of the lungs and brain, and lumbar puncture to rule out dissemination; reducing immunosuppression to control infection; promptly initiating induction combination therapy with an amphotericin B lipid complex and 5-fluorocytosine; preserving the infected engraftment, if possible, in the absence of large fungal masses and abscesses; and extending the length of antifungal therapy when fungal elements persist in tissues.
In conclusion, we found that C. deuterogattii may be transmitted by infected allografts, representing a medical concern in countries to which C. gattii species complex is endemic. Cryptococcosis incidence might be reduced by excluding organ donor candidates with a history of neurologic disease without a clear definition of its etiology. Ensuring that clinicians are trained to recognize and treat this fungal infection would likely further reduce transmission from donors.