Dot assay for determining adhesive interactions between yeasts and bacteria under controlled hydrodynamic conditions

Area of Science:

• Microbiology
• Biomaterials Science
• Surface Science

Background:

• Candida yeasts are part of human microflora and adhere to tissues and biomaterials.
• Yeast-bacteria co-adhesion is common, but definitive assays for surface interactions are lacking.
• Previous methods were slow and showed significant biological variation.

Purpose of the Study:

• To develop a novel assay for simultaneous determination of yeast-bacteria adhesive interactions on surfaces.
• To investigate the influence of different bacterial strains on Candida albicans adhesion.
• To analyze the stability of yeast-bacteria co-adhesion under hydrodynamic stress.

Main Methods:

• A new assay was developed for simultaneous determination of yeast and bacterial adhesion under controlled hydrodynamic conditions.
• Adhesion of Candida albicans ATCC 10261 was studied on an acrylic surface in the presence of various bacterial strains.
• A liquid-air interface was used to challenge the detachment forces of adhering microorganisms.

Main Results:

• The presence of adhering bacteria suppressed Candida albicans adhesion to varying degrees, dependent on the bacterial strain.
• Actinomyces naeslundii showed the strongest suppression of yeast adhesion, while Streptococcus gordonii showed the weakest.
• Most yeasts detached under hydrodynamic stress, while C. albicans on a bare surface formed aggregates.

Conclusions:

• A new, reliable assay for studying yeast-bacteria surface interactions under hydrodynamic conditions has been established.
• The findings suggest that bacteria may actively discourage yeast adhesion rather than engage in direct adhesive interactions.
• Different bacterial strains exhibit varying capacities to inhibit yeast adhesion, highlighting strain-specific effects.