The Case for Adopting the “Species Complex” Nomenclature for the Etiologic Agents of Cryptococcosis

Abstract

Cryptococcosis is a potentially lethal disease of humans/animals caused by Cryptococcus neoformans and Cryptococcus gattii. Distinction between the two species is based on phenotypic and genotypic characteristics. Recently, it was proposed that C. neoformans be divided into two species and C. gattii into five species based on a phylogenetic analysis of 115 isolates. While this proposal adds to the knowledge about the genetic diversity and population structure of cryptococcosis agents, the published genotypes of 2,606 strains have already revealed more genetic diversity than is encompassed by seven species. Naming every clade as a separate species at this juncture will lead to continuing nomenclatural instability. In the absence of biological differences between clades and no consensus about how DNA sequence alone can delineate a species, we recommend using “Cryptococcus neoformans species complex” and “C. gattii species complex” as a practical intermediate step, rather than creating more species. This strategy recognizes genetic diversity without creating confusion.

Diagnosis of invasive fungal diseases in haematology and oncology: 2018 update of the recommendations of the infectious diseases working party of the German society for hematology and medical oncology (AGIHO)

“…In patients with haematological malignancies, IFD involving the central nervous system is usually caused by moulds ( Aspergillus species) . Although only occurring occasionally in this patient group, meningoencephalitis caused by Cryptococcus neoformans (now called “ Cryptococcus neoformans species complex” ) has been described . Typical signs and symptoms of central nervous system infections with Cryptococcus species include headache, altered mental status, nausea, vomiting, deterioration of vision, VI th nerve palsies due to increased cerebrospinal fluid (CSF) opening pressure and psychiatric symptoms.…”

Heterocycle Thiazole Compounds Exhibit Antifungal Activity through Increase in the Production of Reactive Oxygen Species in the Cryptococcus neoformans-Cryptococcus gattii Species Complex

“…All the yeast strains were stored frozen at Ϫ80°C. In this work, we refer to the isolates of different molecular species as the C. neoformans-C. gattii species complex, as a proposed by Kwon-Chung et al (38).…”

Outcomes of cryptococcosis in renal transplant recipients in a less‐resourced health care system

“…Cryptococcosis is a life‐threatening invasive fungal disease caused by an encapsulated yeast, Cryptococcus spp. complex, predominantly represented by Cryptococcus neoformans and C. gattii . Although the majority of infections occur by inhalation of infectious propagules from the environment, the disease can be directly acquired from an infected transplanted organ .…”