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Proteolytic activity of Candida albicans and other yeasts
Abstract:
Clinical isolates of C. albicans (75 strains) and other yeasts (20 strains) were evaluated for their ability to produce a carboxyl acid proteinase in an effort to assess its potential role as a virulence factor. Yeasts were categorized as to the infectious process present in the patient: (1) isolates from patients with invasive disease, (2) isolates from patients with possible invasive disease, (3) isolates from superficially infected patients and (4) isolates from noninfected, colonized patients. Yeasts were grown for 7 days in medium containing bovine serum albumin (BSA) as the sole nitrogen source. The amount of extracellular proteinase was measured at pH 3.2, using BSA as substrate. The majority (97%) of C. albicans isolates produced a detectable proteinase. Some non-C. albicans isolates produced proteinase; however, the amount of activity was generally less than for C. albicans. No correlation was found between the amount of proteolytic activity and the degree of invasiveness of the strains.
Insights
Most Candida albicans clinical isolates produce carboxyl acid proteinase, an enzyme potentially linked to virulence. However, this study found no correlation between proteinase levels and the invasiveness of yeast infections.
Area of Science:
- Medical Mycology
- Microbial Pathogenesis
Background:
- Candida albicans is a common human fungal pathogen.
- Proteinases are enzymes that break down proteins.
- Carboxyl acid proteinase is a type of proteinase produced by some fungi.
Purpose of the Study:
- To investigate the production of carboxyl acid proteinase by clinical isolates of Candida albicans and other yeasts.
- To assess the potential role of this proteinase as a virulence factor in candidiasis.
- To determine if there is a correlation between proteinase activity and the clinical manifestation of infection.
Main Methods:
- Clinical yeast isolates (75 C. albicans, 20 other yeasts) were cultured.
- Yeast strains were categorized based on infection invasiveness.
- Extracellular proteinase production was measured using bovine serum albumin (BSA) as a substrate at pH 3.2.
Main Results:
- The majority (97%) of C. albicans isolates produced detectable carboxyl acid proteinase.
- Non-C. albicans yeasts also produced proteinase, but generally at lower levels.
- No significant correlation was observed between the quantity of proteinase activity and the degree of infection invasiveness.
Conclusions:
- Carboxyl acid proteinase production is a common characteristic of clinical C. albicans isolates.
- The presence and level of this proteinase do not appear to directly correlate with the invasiveness of the infection caused by these yeasts.
- Further research is needed to fully elucidate the role of fungal proteinases in candidiasis pathogenesis.