S. aureus develops biofilms on titanium within 2 weeks in vitro.

Background: The formation of biofilms, characterized by cell aggregation and extracellular polymeric substance (EPS) production, is a common feature of periprosthetic joint infections (PJI).

Objective: The current study aimed to investigate the development of biofilm features in vitro within less than 3 weeks by Staphylococcus aureus isolated from PJIs.

Methods: Biofilms were grown on sandblasted titanium discs, and fluorescence spectroscopy and microscopy were used to observe biofilm maturation for 21 days.

Results: DNA mass decreased initially, then increased from day 5 onwards, and decreased again after day 7. The proportion of living to dead bacteria oscillated until day 7 and increased at day 10 for strain A and day 14 for strain B. EPS mass decreased initially and then continuously increased. Multilayer bacterial organization was observed at day 7.

Conclusion: Cell aggregation occurred during the first week, followed by EPS production in the second week, and characteristic biofilm features were observed within 1 to 2 weeks.