The class Mucormycetes (formerly Zygomycetes) includes a variety of filamentous fungi that may cause life-threatening human diseases and, over the past two decades, have emerged as increasingly important causes of morbidity and mortality among immunocompromised patients. The first case of mucormycosis (zygomycosis) in humans was reported in 1885 by Platauf as Mycosis Mucorina. In many of the cases reported, thereafter, the infection was identified as ‘mucormycosis’ or Mucor infection based solely on histological findings of wide, rarely septate hyphae, without culture confirmation. The use of the term ‘mucormycosis’ was further promoted by the original classification of most of the pathogenic species of Zygomycetes as members of the genus Mucor. Consequently, the term ‘zygomycosis,’ instead of ‘mucormycosis,’ was widely used during the past three decades for infections caused by any of the species within the class of Zygomycetes. Many experts preferred the use of ‘mucormycosis’ and emphasized that the opportunistic disease due to those fungi in the order Mucorales differed substantially from those caused by members of the order Entomophthorales, which was also included within the class Zygomycetes. Diseases caused by members of the order Mucorales, such as Rhizopus oryzae, are typically opportunistic infections of the lungs, sinuses, and brain with angioinvasion leading to ischemia, infarction, and necrosis. Diseases caused by members of order Entomophthorales, such as Conidiobolus spp. and Basidiobolus spp., are typically subcutaneous infections in immunocompetent hosts. With advances in molecular taxonomy, these clinical and pathophysiological distinctions correlated with the observation that the class of Zygomycetes is not monophyletic. Thus, the Zygomycota was eliminated. The taxa, conventionally classified in Zygomycota, are now distributed among the new phylum Glomeromycota and four subphyla, including the Mucoromycotina and Entomophthoromycotina. As the orders Mucorales and Entomophthorales are preserved, the preferred names for the respective diseases should now be mucormycosis and entomophthoromycosis. The focus of this chapter is mucormycosis. See chapt. 22 in this text for discussion of entomophthoromycosis.
- Lichtheimia (formerly Absidia)
ASJC Scopus subject areas
- Immunology and Microbiology(all)