Submitted to: Medical Mycology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/2/2011
Publication Date: 10/1/2011
Citation: Schell, W.A., O Donnell, K., Alspaugh, J.A. 2011. Heterothallic mating in Mucor irregularis and first isolate of the species outside of Asia. Medical Mycology. 2011(49)714-723. Interpretive Summary: Fungi of the genus Mucor can cause serious illness in humans, particularly among people with compromised immune systems. Diagnosis and treatment of Mucor infections requires accurate identification, and can be assisted by DNA sequence analyses. In order to identify an unusual fungus responsible for an infection in a patient previously diagnosed with acute myeloblastic leukemia, a pure culture derived from a biopsy of the infected area was studied microscopically and it was also typed molecularly using DNA sequence data. The morphological and molecular data both identified the pathogen as Mucor irregularis, which represents the first human infection caused by this fungus within the United States, and the first outside of Asia. The Mucor infection was treated successfully with the antifungal drug amphotericin B. The results of this study should be of interest to clinical microbiologists, infectious disease specialists, and fungal biologists interested in the spectrum of human pathogenic fungi and their treatment with antifungals.
Technical Abstract: This study reports on the discovery of heterothallic mating in Mucor irregularis (formerly Rhizomucor variabilis var. variabilis) and it extends the range of this species from Asia to the United States. We report on a case of primary cutaneous mucormycosis, involving the forearms of a cotton farmer from North Carolina, in which the infection was cured using amphotericin B therapy. Intraspecific crosses between the North Carolina strain DUMC 150.04 and M. irregularis CBS 103.93, the ex-type strain of R. variabilis var. variabilis from China, resulted in the formation of abundant fertile zygospores. By way of contrast, interspecific crosses between the North Carolina isolate and the ex-neotype strain of M. hiemalis NRRL 3624 resulted in the formation of putative azygospores by M. irregularis DUMC 150.04.