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United States Department of Agriculture

Agricultural Research Service

Research Project: Genomic Analyses and Management of Agricultural and Industrial Microbial Genetic Resources and Associated Information

Location: Bacterial Foodborne Pathogens & Mycology Research Unit

Title: Fusarium and other opportunistic hyaline fungi

Authors
item Zhang, Sean -
item O`donnell, Kerry
item Sutton, Deanna -

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: November 19, 2013
Publication Date: N/A

Technical Abstract: This chapter focuses on those fungi that grow in tissue in the form of hyaline or lightly colored, septate hyphae. These fungi include Fusarium and other hyaline fungi. Human disease caused by hyaline fungi is called hyalophyphomycosis. Most of the hyaline fungi described in this chapter only produce asexual anamorphs in culture. Prior to the application of molecular systematics, many of these moulds were classified in the artificial class Hyphomycetes (genera which bear their conidia free). Phenotypic/morphologic identification of hyaline Hyphomycetes is based on conidiogenesis; however, accurate species level identification frequently requires DNA sequence data from one or more informative loci. Molecular phylogenetic analysis has revealed that several Fusarium morphospecies actually represent species-rich species complexes. Fusarioses are most frequently caused by members of the following six species complexes: F. solani, F. oxysporum, F. fujikuroi, F. incarntum-F.equiseti, F. chlamydosporum, and F. dimerum. Fusarium species are cosmopolitan soil saprobes that can cause toxicosis or infection in humans. A frequent infection in the immunocompetent humans is keratitis resulting from trauma or contamination of contact lenses/solutions. Severe disseminated fusarial infections, which show low survival rates, are seen in patients with hematological malignancy and allogenic hematopoietic stem cell transplant. The portal of entry is unknown in most cases of invasive fusarial infections; however, inhalation of airborne conidia appears to be the most common mode of transmission. Other hyaline fungi can cause human infection as well, ranging from cutaneous to disseminated, systemic invasive infections. In general, the recovery of a hyaline fungus from a normally sterile site and microscopic evidence of tissue damage provide the most convincing evidence of invasive disease. Early diagnosis of invasive hyalohyphomycosis caused by a hyaline fungus is often key to appropriate management strategies.

Last Modified: 9/2/2014
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