Biofilm formation on silicone tympanostomy tubes with polyvinylpyrrolidone coating.

OBJECTIVE To determine whether biofilm formation on silicone tympanostomy tubes (TTs) is prevented by polyvinylpyrrolidone (PVP) coating. DESIGN In vitro microbiologic study. SUBJECTS Silicone TTs with and without a PVP coating. INTERVENTION The TTs were exposed to blood or phosphate-buffered saline and cultured with Pseudomonas aeruginosa or Staphylococcus aureus. After 4 days, antibiotics were added to kill planktonic bacteria. Biofilm formation was assessed by quantitative bacterial counts and scanning electron microscopy. RESULTS Human blood enhanced S aureus biofilm formation on TTs with and without PVP (P < .001). Staphylococcus aureus biofilm formation was similar on TTs with and without PVP coating. Pseudomonas aeruginosa biofilm formation was less on TTs with PVP coating after exposure to phosphate-buffered saline (P = .04), but this difference was not significant after blood exposure (P = .19). CONCLUSIONS Polyvinylpyrrolidone coating of TTs imparts resistance to P aeruginosa biofilm formation. The clinical impact of PVP on TTs may be attenuated by exposure to blood, but this will require study in clinical trials.