Inhibitory effect of chlorhexidine on biofilm formation by prosthetic surface pathogens: An in vitro study

Objective: The research investigated how 0.12% chlorhexidine affects the initial growth of single-species biofilms, which include typical prosthetic surface bacteria that colonise different types of prosthetic materials. Methods: Discs of titanium, zirconia, cobalt-chromium alloy, PMMA, and PEEK were inoculated with five common prosthetic pathogens (S. aureus, S. mutans, E. faecalis, C. albicans, P. aeruginosa). After 24-hour biofilm formation, specimens were treated with 0.12% CHX for 60 seconds. Biofilm biomass was assessed by crystal violet staining and CFU enumeration. Results: The tested materials showed decreased early biofilm development after Chlorhexidine exposure at different levels, which depended on material surfaces and bacterial species. The surface materials of titanium and zirconia showed the most significant decrease in biofilm biomass, but PMMA and PEEK surfaces maintained more biofilm than the other materials. The susceptibility tests showed that S. aureus and S. mutans became more responsive to chlorhexidine treatment, yet C. albicans and P. aeruginosa developed stronger resistance against the treatment. Conclusion: Chlorhexidine shows different levels of biofilm inhibition on prosthetic implant surfaces when tested under laboratory conditions based on both the material used and the species being studied. The research results confirm that chlorhexidine should be used as an additional measure for prosthesis cleaning, but the study shows that choosing the right materials remains essential to prevent biofilm-related problems. The research needs additional investigations, which should include surface analysis and multiple species biofilm experiments.