Characterization of the interaction between Candida albicans and probiotic bacteria or, How do probiotics affect yeast infections? or, Presented by: Kerry Quinn-Swift Presented by: Kerry Quinn-Swift

Candida albicans Yeast infections can occur in many places: Orally, it is called thrush The skin Under nails Genitals Primarily occurs in infants, women, and immunocompromised individuals. C. albicans is the primary infective species of Candida. C. albicans can be drug resistant. Oral thrush Skin infection

Drug resistance mechanism of C. albicans Drug susceptible yeast cells like the top half of the circle only contain a few drug resistance pumps. Drug resistant cells contain many more, as well as point mutations preventing the drug from acting on the target enzyme in the cell.

Probiotic bacteria Probiotics are live microorganisms which, when administered in adequate amounts, confer a health benefit on the host. Probiotics are hypothesized to create health benefits through some of the following mechanisms:  Competition for surface attachment and nutrients  Metabolic effects, like decreasing the pH  Anti-inflammatory and immune effects

Our Study  How do probiotics help fight Candida albicans?  We compared a drug susceptible strain of C. albicans to the same strain after it developed drug resistance.  We used two well known strains of probiotics: Lactobacillus rhamnosus GR-1 Lactobacillus reuteri RC-14 A control lactobacilli isolated from a prairie vole.

Results Growth Assays: Yeast grown with anti-fungal drugs and probiotic colony. Live/Dead fluorescent staining of yeast cells.

Results Gene Expression Study: Found that drug resistance genes were decreased In the presence of probiotics In low levels of pH

Conclusions Growth inhibition may be caused by lactic acid production from the lactobacilli. – Probiotics decrease the pH of their environment. – A decrease in pH level inhibits the growth of C. albicans. Probiotics decrease drug resistance gene expression. – Probiotic treatment may increase the effectiveness of antifungal treatment in drug resistant strains of C. albicans. Lactobacilli probiotic bacteria may aid in the treatment of yeast infections, as well as prevention.

Thank you! This opportunity was made possible by OK INBRE. Special thanks: TCC Biotechnology department OSU Center for Health Sciences Dr. Gerwald Kohler Dr. Senait Assefa