Pathogenicity of Saccharomyces cerevisiae in complement factor five-deficient mice

Area of Science:

• Microbiology
• Immunology
• Infectious Diseases

Background:

• Previous studies determined Saccharomyces cerevisiae isolate virulence using CD-1 mice, with non-fatal infections.
• Further characterization of S. cerevisiae pathogenesis is needed, particularly in immune-deficient models.

Purpose of the Study:

• To investigate the role of Complement component 5 (C5) in host resistance against S. cerevisiae infections.
• To compare the virulence of a clinical isolate (YJM128) and an avirulent isolate (Y55) in C5-deficient mice.

Main Methods:

• Intravenous infection of DBA/2N mice (C5-deficient) and C5-competent mice with S. cerevisiae isolates YJM128 and Y55.
• Quantification of yeast cell burdens in various organs over time.
• Mortality assessment in infected mice.
• Comparison of virulence between different mouse strains and S. cerevisiae isolates.

Main Results:

• In C5-deficient mice, the virulent isolate YJM128 caused significant mortality (90% with 10(7) CFU) and organ burden increases, especially in the brain and kidneys.
• The avirulent isolate Y55 did not cause mortality and showed decreased burdens in kidneys and brain.
• C5-deficient mice were significantly more susceptible to S. cerevisiae infection compared to C5-competent mice, with higher mortality and yeast burdens.
• Seven of ten other S. cerevisiae isolates demonstrated increased virulence in DBA/2N mice, causing at least 40% mortality.

Conclusions:

• Complement component 5 (C5) plays a critical role in host defense against S. cerevisiae infections.
• Certain S. cerevisiae isolates possess significant pathogenic potential, particularly in the context of compromised complement function.
• The C5-deficient mouse model is valuable for studying S. cerevisiae pathogenesis and host-pathogen interactions.