Enterococcus faecalis surface proteins determine its adhesion mechanism to bile drain materials

Area of Science:

• Microbiology
• Biomaterials Science
• Infectious Diseases

Background:

• Bacterial adhesion to medical devices is a critical factor in device-associated infections.
• Enterococcus faecalis is a common pathogen implicated in biliary tract infections.

Purpose of the Study:

• To investigate the role of specific Enterococcus faecalis surface proteins in bacterial adhesion to common biliary drain materials.
• To elucidate the mechanisms by which these proteins mediate adhesion.

Main Methods:

• Utilized isogenic E. faecalis strains lacking or expressing specific surface proteins (enterococcal surface protein, aggregation substances 1 and 373).
• Measured bacterial adhesion kinetics to silicone rubber, fluoro-ethylene-propylene, and polyethylene using in situ parallel plate flow chambers.
• Employed nearest neighbor analysis to assess bacterial adhesion patterns and cooperativity.

Main Results:

• All E. faecalis strains showed similar initial deposition rates on drain materials.
• The presence of surface proteins significantly increased the total number of adhering bacteria.
• Enterococci expressing aggregation substances 1 or 373 exhibited enhanced adhesion through positive cooperativity, where initial adhesion promotes further bacterial attachment.

Conclusions:

• Enterococcus faecalis surface proteins, particularly aggregation substances, are crucial for robust adhesion to biliary drain materials.
• These proteins mediate adhesion via mechanisms including positive cooperativity, contributing to the pathogenesis of biliary drain-associated infections.