Effect of Blood and Mucus on Tympanostomy Tube Biofilm Formation

Objective/Hypothesis: Tympanostomy tube (TT) biofilm formation may lead to refractory otorrhea and occlusion. The aim of this study was to determine whether TT biofilm formation may be promoted by mucus or blood exposure. Study Design: In vitro, controlled. Methods: Fluoroplastic TTs were exposed to blood, mucoid effusion or saline. Half were allowed to dry. TTs were cultured with Pseudomonas aeruginosa. After 4 days, gentamicin was added to kill planktonic bacteria. Biofilm formation was assessed by quantitative bacterial counts and scanning electron microscopy. Results: Mucus pretreatment (dry and wet) did not increase biofilm formation. Both dry and wet blood exposure increased biofilm formation by bacterial counts (P < .0001). Biofilm formation was demonstrated by electron microscopy in all groups. Conclusion: P. aeruginosa biofilm formation on fluoroplastic TTs is enhanced by blood exposure. Care should be taken to minimize bleeding with TT placement to reduce the risk of biofilm formation.