Phenotypic switching in Cryptococcus neoformans

Bettina C. Fries, David L. Goldman, Arturo Casadevall

Research output: Contribution to journalReview articlepeer-review

33 Scopus citations


Cryptococcus neoformans strains exhibit considerable phenotype variability with regards to the capsular polysaccharide, sterol composition of the cell wall, and cell and colony morphology. Phenotypic changes can occur spontaneously during in vitro passage of strains or during chronic infection in vivo and may be associated with differences in virulence. Studies from our laboratory have demonstrated that phenotype variability can be the result of phenotypic switching. Phenotypic switching is defined as a reversible change of an observable colony phenotype that occurs at a frequency above the expected frequency for somatic mutations. This implies that phenotypic switching represents controlled and programmed changes in this pathogenic yeast rather than random mutations. We have shown that a phenotypic switch from a smooth colony phenotype to a mucoid colony phenotype occurs in vitro and in vivo during chronic infection of mice. More importantly we have now demonstrated that the switch is associated with an increase in virulence and a change in the host immune response. Implications of these findings for the pathogenesis of cryptococcosis are discussed.

Original languageEnglish (US)
Pages (from-to)1345-1352
Number of pages8
JournalMicrobes and Infection
Issue number13
StatePublished - Nov 1 2002


  • Colony morphology
  • Fungus
  • Microevolution
  • Phenotypic switching
  • Virulence

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Infectious Diseases


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