The bacillithiol pathway is required for biofilm formation in Staphylococcus aureus

Area of Science:

• Microbiology
• Bacterial Pathogenesis
• Biofilm Formation

Background:

• Staphylococcus aureus is a significant human pathogen causing diverse infections.
• Biofilms enable S. aureus to resist host defenses and antimicrobial agents.
• S. aureus employs low molecular weight (LMW) thiols like bacillithiol (BSH) and nitric oxide (NO) to counteract host stress.

Purpose of the Study:

• To investigate the role of bacillithiol (BSH) in S. aureus biofilm formation.
• To explore the involvement of nitric oxide (NO) and its related enzymes in S. aureus biofilms.
• To elucidate the interplay between oxidative/nitrosative stress and S. aureus biofilm development.

Main Methods:

• Generated and analyzed a Staphylococcus aureus bshC mutant strain lacking BSH.
• Identified and analyzed a putative S-nitrosobacillithiol reductase (BSNOR) and its corresponding mutant strain.
• Assessed the impact of acidified sodium nitrite on S. aureus biofilm thickness.

Main Results:

• The bshC mutant deficient in BSH showed impaired biofilm formation.
• The putative bsnoR mutant exhibited reduced BSH levels and decreased biofilm formation.
• Nitric oxide (NO) was found to be important for biofilm formation, with acidified sodium nitrite significantly reducing biofilm thickness.

Conclusions:

• Bacillithiol (BSH) is essential for normal biofilm formation in Staphylococcus aureus.
• Nitric oxide (NO) plays a critical role in S. aureus biofilm development.
• BSH and NO are key mediators in the response to oxidative and nitrosative stress during S. aureus biofilm formation.