Proteome of Staphylococcus aureus biofilm changes signifi-cantly with aging

Staphylococcus aureus is a notorious biofilm-producing pathogen that is frequently isolated from implantable medical device infections. As biofilm ages, it becomes more tolerant to antimicrobial treatment leading to treatment failure and necessitating the costly removal of infected devices. In this study, we investigated what changes occur in the proteome of S. aureus biofilm grown for 3-days and 12-days in comparison with 24 h planktonic showed that proteins associated with bi-osynthetic processes, ABC transporter pathway, virulence proteins, and shikimate kinase pathway were significantly upregulated in 3-day biofilm, while proteins associated with sugar transporter, degradation, and stress response were downregulated. In 12-day biofilms, proteins associated with peptidoglycan biosynthesis, sugar transporters, and stress responses were upregulated, whereas proteins associated with ABC transporters, DNA replication, and adhesion proteins were down-regulated. Furthermore, we observed significant variations in the formation of biofilms result from changes in the level of metabolic activity in the different growth mode of biofilms that could be a significant factor of S. aureus biofilm maturation and persistence. Collectively, potential marker proteins were identified and further characterized to understand their exact role in S. aureus biofilm development which may shed light on possible new therapeutic regimes in the treatment of biofilm-related implant-associated infections.