Esp-independent biofilm formation by Enterococcus faecalis

Area of Science:

• Microbiology
• Bacterial pathogenesis
• Medical microbiology

Background:

• Enterococcus faecalis is an opportunistic pathogen frequently found in biofilms on medical devices.
• The molecular mechanisms governing E. faecalis biofilm formation are not fully understood.
• The Esp cell surface protein has been implicated in E. faecalis biofilm development.

Purpose of the Study:

• To investigate the role of the Esp protein in E. faecalis biofilm formation.
• To elucidate the mechanisms underlying E. faecalis biofilm development.
• To determine the influence of environmental conditions and other factors on E. faecalis biofilm formation.

Main Methods:

• Microtiter plate assays were used to assess biofilm formation.
• A chemostat-based biofilm fermentor system was employed for detailed biofilm analysis.
• Scanning electron microscopy (SEM) was utilized to visualize biofilm structure.
• Genetically modified E. faecalis strains lacking esp were examined.

Main Results:

• E. faecalis forms biofilms even in the absence of the esp gene and its associated pathogenicity island.
• Biofilm development progresses through distinct stages: attachment, microcolony formation, and maturation with water channels.
• Environmental conditions significantly modulate E. faecalis biofilm formation and maintenance.
• The secreted metalloprotease GelE was found to enhance biofilm formation.

Conclusions:

• The Esp surface protein is dispensable for Enterococcus faecalis biofilm formation.
• E. faecalis biofilm formation is a complex, environmentally sensitive process.
• GelE plays a role in enhancing E. faecalis biofilm development.