Lactobacillus rhamnosus may change the virulence of Candida albicans

To investigate the influence of Lactobacillus rhamnosus in the expression of virulence factors of Candida albicans in vitro. A suspension of L. rhamnosus was initially grown in MRS agar. The other day, Sabouraud dextrose agar was added on the growth of lactobacilli and C. albicans was seeded for 24, 48 and 72 hours. Candida strains were then isolated for investigation of the ability of biofilm formation, by means of cultivation into 96 wells plaque, and reading the optical densities and counting colony forming units per mL. Also the ability of germ tube formation was investigated, after incubation in horse serum and counting of 200 cells. The results were compared to Candida strains grown in the absence of L. rhamnosus, using Student's t test for statistical analysis. there was a significant reduction in the growth of C. albicans in the presence of lactobacilli after 24, 48 or 72 hours. Significant reduction was also observed in germ tube formation after interaction for 48 or 72 hours. For biofilm formation, no statistically significant difference was observed between the Candida strains grown in the presence or absence of lactobacilli. The results suggest that L. rhamnosus is able to influence significantly the growth and expression of virulence factors of C. albicans in vitro, and may interfere with pathogenicity of these micro-organisms.