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Pathogenicity of morphological and auxotrophic mutants of Candida albicans in experimental infections
Abstract:
The relative pathogenicities of yeast and mycelial forms of Candida albicans were determined after intravenous injection of the two forms into mice. Yeast and mycelial forms of C. albicans CMI45348 were prepared in chemostat culture. Both morphological forms were pathogenic, but the histology of kidney sections always showed a mixture of the yeast and mycelial elements of the organism. Similarly, infection of mice with prototrophic strains produced a mixture of morphological forms at the site of infection. The yeast (CA2) and mycelial (hOG301) morphological mutants of C. albicans were pathogenic, and sections from the kidneys of the infected mice showed that the mutants retained their original morphological forms. These data indicate that both the yeast and mycelial forms of C. albicans can adhere, invade, and proliferate in an infected host. Auxotrophic diploid mutants were nonpathogenic. However, construction of a prototrophic tetraploid strain from two auxotrophs restored the pathogenicity of the organism.
Insights
Both yeast and mycelial forms of Candida albicans are pathogenic, contributing to infection. Morphological mutants retained pathogenicity, while auxotrophic mutants were nonpathogenic, highlighting the importance of prototrophy in C. albicans virulence.
Area of Science:
- Mycology
- Pathogen Biology
- Medical Microbiology
Background:
- Candida albicans exists in yeast and mycelial forms.
- Understanding the role of morphology in C. albicans pathogenesis is crucial.
Purpose of the Study:
- To determine the relative pathogenicities of yeast and mycelial forms of C. albicans.
- To investigate the role of specific morphological mutants and prototrophy in C. albicans virulence.
Main Methods:
- Intravenous injection of yeast and mycelial forms of C. albicans into mice.
- Preparation of C. albicans forms and mutants using chemostat culture.
- Histological examination of infected host tissues (kidneys).
Main Results:
- Both yeast and mycelial forms of wild-type C. albicans were pathogenic in mice.
- Infections with wild-type strains resulted in mixed yeast and mycelial elements in host tissues.
- Specific yeast (CA2) and mycelial (hOG301) mutants retained their original morphologies and pathogenicity.
- Auxotrophic diploid mutants were nonpathogenic, but restoring prototrophy (tetraploid strain) restored pathogenicity.
Conclusions:
- Both yeast and mycelial forms of C. albicans can adhere, invade, and proliferate in the host.
- Morphological form alone does not determine pathogenicity; other factors like prototrophy are critical.
- Prototrophy is essential for C. albicans virulence and pathogenicity in a host environment.