Molecular detection and identification of zygomycetes species from paraffin-embedded tissues in a murine model of disseminated zygomycosis: a collaborative European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Fungal Infection Study Group (EFISG) evaluation.

The present study was performed to assess the interlaboratory reproducibility of the molecular detection and identification of species of Zygomycetes from formalin-fixed paraffin-embedded kidney and brain tissues obtained from experimentally infected mice. Animals were infected with one of five species (Rhizopus oryzae, Rhizopus microsporus, Lichtheimia corymbifera, Rhizomucor pusillus, and Mucor circinelloides). Samples with 1, 10, or 30 slide cuts of the tissues were prepared from each paraffin block, the sample identities were blinded for analysis, and the samples were mailed to each of seven laboratories for the assessment of sensitivity. A protocol describing the extraction method and the PCR amplification procedure was provided. The internal transcribed spacer 1 (ITS1) region was amplified by PCR with the fungal universal primers ITS1 and ITS2 and sequenced. As negative results were obtained for 93% of the tissue specimens infected by M. circinelloides, the data for this species were excluded from the analysis. Positive PCR results were obtained for 93% (52/56), 89% (50/56), and 27% (15/56) of the samples with 30, 10, and 1 slide cuts, respectively. There were minor differences, depending on the organ tissue, fungal species, and laboratory. Correct species identification was possible for 100% (30 cuts), 98% (10 cuts), and 93% (1 cut) of the cases. With the protocol used in the present study, the interlaboratory reproducibility of ITS sequencing for the identification of major Zygomycetes species from formalin-fixed paraffin-embedded tissues can reach 100%, when enough material is available.

Failure of voriconazole to cure disseminated zygomycosis in an immunocompromised child.

Voriconazole is increasingly used as a first-line agent for empirical antifungal therapy of prolonged febrile neutropenia in paediatric cancer patients. We describe the case of a 9-year-old patient with stage IV Burkitt lymphoma, who developed pulmonary and splenic zygomycosis while receiving voriconazole for persistent febrile neutropenia. The causative agent, Absidia corymbifera, was identified by broad-range fungal PCR in a lung biopsy sample. The patient was successfully treated with a combination of partial resection of the left upper lobe and antifungal therapy with high-dose liposomal amphotericin B followed by oral itraconazole as demonstrated by resolving pulmonary infiltrates on serial high resolution CT scans. CONCLUSION: This case emphasises that the lack of in vitro activity of voriconazole against zygomycetes is clinically relevant. Failure of voriconazole in suspected fungal infection should be investigated for the possibility of zygomycosis. Broad-range polymerase chain reaction may be able to identify the causative organism when cultures remain sterile.

Disseminated Rhizopus microsporus infection cured by salvage allogeneic hematopoietic stem cell transplantation, antifungal combination therapy, and surgical resection.

O. Lebeau, C. Van Delden, J. Garbino, J. Robert, F. Lamoth, J. Passweg, Y. Chalandon. Disseminated Rhizopus microsporus infection cured by salvage allogeneic hematopoietic stem cell transplantation, antifungal combination therapy, and surgical resection. Transpl Infect Dis 2010. All rights reserved Abstract: Invasive Zygomycetes infection complicating prolonged neutropenia is associated with high mortality in the absence of immune recovery. We report a patient who developed disseminated zygomycosis due to Rhizopus microsporus during induction chemotherapy for acute myeloid leukemia. Rescue allogeneic hematopoietic stem cell transplantation (allo-HSCT) was performed as her only chance of cure of this infection and to treat refractory leukemia. Posaconazole combined with liposomal amphotericin B contained the zygomycosis during prolonged neutropenia due to allo-HSCT followed by intense immunosuppression for grade IV acute graft-versus-host disease. Surgical removal of all infected sites after immune recovery, with prolonged posaconazole treatment, ultimately cured the infection. New combination antifungal therapies might sufficiently control disseminated zygomycosis to allow allo-HSCT to be performed, assuring life-saving immune recovery. Surgery appears to be necessary for definite cure of these infections.