Controlling Streptococcus mutans and Staphylococcus aureus biofilms with direct current and chlorhexidine

Area of Science:

• Microbiology
• Biomaterials Science
• Infectious Diseases

Background:

• Microbial biofilms on biomaterials are a primary cause of persistent infections.
• Gram-positive bacteria, including Streptococcus mutans and Staphylococcus aureus, are key pathogens in dental caries and medical implant infections.
• Existing antimicrobial treatments struggle to eradicate established biofilms, necessitating novel therapeutic approaches.

Purpose of the Study:

• To investigate the efficacy of low-level direct current (DC) in eliminating biofilm cells of Streptococcus mutans and Staphylococcus aureus.
• To evaluate the synergistic effect of concurrent treatment with DC and chlorhexidine (CHX) on biofilm viability.

Main Methods:

• Biofilm cultures of Streptococcus mutans and Staphylococcus aureus were subjected to low-level direct current (DC).
• Concurrent treatment involving DC and low concentrations of chlorhexidine (CHX) was applied.
• Bacterial viability within biofilms was assessed post-treatment.

Main Results:

• Low-level DC significantly reduced the viability of biofilm cells for both S. mutans and S. aureus.
• A synergistic effect was observed when DC was combined with chlorhexidine (CHX) at low concentrations.
• Treatment with 28 µA/cm² DC and 50 µg/mL CHX for 1 hour reduced S. aureus viability by approximately 5 logs and S. mutans by 4 logs.

Conclusions:

• Low-level direct current presents a promising method for eradicating pathogenic bacterial biofilms.
• The combination of DC and chlorhexidine offers enhanced efficacy in disrupting established biofilms.
• These findings pave the way for developing improved strategies against chronic biofilm-associated infections.