Phospholipase and protease activity of human intestinal yeast under various cultivation conditions

Prokopiev V.V., Karabasova Е.B., Kraft L.A., Kuklina N.V., Yurova V.A.

Clinical diagnostic laboratory «Zdorovie», Barnaul
Altai State Medical University, Barnaul, Russia

Aim. To evaluate the protease and phospholipase activity of intestinal strains of basidiomycete (Rhodotorula mucilaginosa, Trichosporon spp.) and ascomycete (Candida albicans, Geotrichum candidum, Pichia spp., Wickerhamiella pararugosa, Coniochaeta hoffmannii, Brettanomyces bruxellensis) yeasts under different temperature conditions, aerobic, anaerobic and hypercapnic conditions.
Methods. Phospholipase activity was assessed by the diameter of the precipitation zone around the studied microorganisms on yolk agar. Protease activity was assessed by measuring the unstained (0.5% amido-black) zone after incubation on a medium containing 0.2% bovine serum albumin. The evaluation was carried out after 96 hours under aerobic conditions at 37°C and 25°C, under hypercapnic conditions (10% CO2) at 37°C and under anaerobic conditions at 25°C.
Results. C. albicans exhibited phospholipase activity under all culture conditions. P. kudriavzevii and G. candidum exhibited phospholipase activity under aerobic and hypercapnic conditions. Rh. mucilaginosa degraded phospholipids only under aerobic conditions. Proteolytic activity under aerobic conditions and in the presence of 10% CO2 was exhibited only by C. albicans and P. kudriavzevii.
Conclusions. The metabolic ability of C. albicans and P. kudriavzevii under various temperature and oxygen conditions, similar to the conditions of various biotopes of the human body, allows for the substantiation of high pathogenic potential of these micromycetes. The lack of proteolytic activity in G. candidum and Rh. mucilaginosa suggests low pathogenic potential or the presence of other factors contributing to human disease.