Mucor germinans, a novel dimorphic species resembling Paracoccidioides in a clinical sample: questions on ecological strategy
Na Li,
Jennifer Bowling,
Sybren de Hoog,
Chioma I. Aneke,
Jung-Ho Youn,
Sherin Shahegh,
Jennifer Cuellar-Rodriguez,
Christopher G. Kanakry,
Maria Rodriguez Pena,
Sarah A. Ahmed,
Abdullah M. S. Al-Hatmi,
Ali Tolooe,
Grit Walther,
Kyung J. Kwon-Chung,
Yingqian Kang,
Hyang Burm Lee,
Amir Seyedmousavi
Affiliations
Na Li
Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education of Guizhou, Guizhou Medical University, Guiyang, China
Jennifer Bowling
Microbiology Service, Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
Sybren de Hoog
Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education of Guizhou, Guizhou Medical University, Guiyang, China
Chioma I. Aneke
Microbiology Service, Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
Jung-Ho Youn
Microbiology Service, Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
Sherin Shahegh
Microbiology Service, Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
Jennifer Cuellar-Rodriguez
Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
Christopher G. Kanakry
Center for Immuno-Oncology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
Maria Rodriguez Pena
Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
Sarah A. Ahmed
RadboudUMC-CWZ Center for Expertise in Mycology, Nijmegen, the Netherlands
Abdullah M. S. Al-Hatmi
Natural and Medical Sciences Research Centre, University of Nizwa, Nizwa, Oman
Ali Tolooe
Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
Grit Walther
German National Reference Center for Invasive Fungal Infections, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute, Jena, Germany
Kyung J. Kwon-Chung
Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
Yingqian Kang
Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education of Guizhou, Guizhou Medical University, Guiyang, China
Hyang Burm Lee
Environmental Microbiology Laboratory, Department of Agricultural Biological Chemistry, College of Agriculture and Life Sciences, Chonnam National University, Gwangju, South Korea
Amir Seyedmousavi
Microbiology Service, Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
ABSTRACT Dimorphism is known among the etiologic agents of endemic mycoses as well as in filamentous Mucorales. Under appropriate thermal conditions, mononuclear yeast forms alternate with multi-nucleate hyphae. Here, we describe a dimorphic mucoralean fungus obtained from the sputum of a patient with Burkitt lymphoma and ongoing graft-versus-host reactions. The fungus is described as Mucor germinans sp. nov. Laboratory studies were performed to simulate temperature-dependent dimorphism, with two environmental strains Mucor circinelloides and Mucor kunryangriensis as controls. Both strains could be induced to form multinucleate arthrospores and subsequent yeast-like cells in vitro. Multilateral yeast cells emerge in all three Mucor species at elevated temperatures. This morphological transformation appears to occur at body temperature since the yeast-like cells were observed in the lungs of our immunocompromised patient. The microscopic appearance of the yeast-like cells in the clinical samples is easily confused with that of Paracoccidioides. The ecological role of yeast forms in Mucorales is discussed.IMPORTANCEMucormycosis is a devastating disease with high morbidity and mortality in susceptible patients. Accurate diagnosis is required for timely clinical management since antifungal susceptibility differs between species. Irregular hyphal elements are usually taken as the hallmark of mucormycosis, but here, we show that some species may also produce yeast-like cells, potentially being mistaken for Candida or Paracoccidioides. We demonstrate that the dimorphic transition is common in Mucor species and can be driven by many factors. The multi-nucleate yeast-like cells provide an effective parameter to distinguish mucoralean infections from similar yeast-like species in clinical samples.
