Role of Biofilms in Post-Tympanostomy Tube Otorrhea

Objective: Nearly half of children who undergo tympanostomy tube (TT) insertion may experience otorrhea following surgery. We sought to review the evidence for the role of bacterial biofilms in post-tympanostomy tube otorrhea (PTTO) and the accumulated experience regarding the preventive measures for biofilm formation/adhesion on TTs. Methods: English literature search for relevant MeSH keywords was conducted in the following databases: MEDLINE (via PubMed), Ovid Medline, Google Scholar, and Clinical Evidence (BMJ Publishing) between January 1, 1995, and December 31, 2019. Subsequently, articles were reviewed and included if biofilm was evident in PTTO. Results: There is an increased evidence supporting the role of biofilms in PTTO. Studies on TT design and material suggest that nitinol and/or silicone TTs had a lower risk for PTTO and that biofilms appeared in specific areas, such as the perpendicular junction of the T-tubes and the round rims of the Paparella-type tubes. Biofilm-component DNAB-II protein family was present in half of children with PTTO, and targeting this protein may lead to biofilm collapse and serve as a potential strategy for PTTO treatment. Novel approaches for the prevention of biofilm-associated PTTO include changing the inherent tube composition; tube coating with antibiotics, polymers, plant extracts, or other biofilm-resistant materials; impregnation with antimicrobial compounds; and surface alterations by ion-bombardment or surface ionization, which are still under laboratory investigation. Conclusions: Currently, there is no type of TT on which bacteria will not adhere. The challenges of treating PTTO indicate the need for further research in optimization of TT design, composition, and coating.