Influence of Streptococcus mutans on Enterococcus faecalis biofilm formation

Area of Science:

• Microbiology
• Oral Health
• Infectious Diseases

Background:

• Enterococcus faecalis is a key pathogen in root canal infections, with biofilm formation being a critical virulence factor.
• Previous research primarily focused on Enterococcus faecalis monocultures, neglecting polymicrobial interactions.
• Understanding Enterococcus faecalis biofilm dynamics in mixed microbial communities is essential for effective treatment strategies.

Purpose of the Study:

• To investigate the influence of Streptococcus mutans biofilms on the biofilm formation of clinical Enterococcus faecalis strains.
• To determine if the interaction between Enterococcus faecalis and Streptococcus mutans is consistent across different Enterococcus faecalis strains.

Main Methods:

• Eight clinical strains of Enterococcus faecalis were cultured on hydroxyapatite disks.
• Biofilm formation was assessed in the presence and absence of a pre-existing Streptococcus mutans biofilm.
• Quantification of viable Enterococcus faecalis cells within biofilms was performed.

Main Results:

• Enterococcus faecalis biofilm formation was significantly enhanced in the presence of Streptococcus mutans for some strains.
• This interaction was strain-dependent, with specific Enterococcus faecalis strains showing no significant change in biofilm formation.
• Three strains (AA-OR34, ER5/1, V583) demonstrated unaffected biofilm formation when co-cultured with Streptococcus mutans.

Conclusions:

• The study highlights significant strain-specific variations in Enterococcus faecalis biofilm formation when interacting with Streptococcus mutans.
• These findings underscore the necessity of employing multispecies models to accurately study biofilm development in polymicrobial infections.
• Results emphasize the complexity of Enterococcus faecalis behavior in mixed microbial environments, relevant to endodontic treatment outcomes.