Evidence of bacterial biofilms in a rabbit model of sinusitis.

BACKGROUND: Bacterial biofilms have been documented on middle ear mucosa, tonsils, and cholesteatoma. In addition, we have described previously bacterial biofilms on frontal recess stents placed during surgery for chronic sinusitis. We hypothesize that bacterial biofilms are present on the mucosa of animals with sinuses experimentally infected with Pseudomonas aeruginosa.

METHODS: We instilled Pseudomonas aeruginosa at log phase growth into the right maxillary sinus in 22 New Zealand white rabbits and harvested specimens 1-20 days later. We then examined the tissues with scanning electron microscopy (SEM) and light microscopy. Mucosa from the middle turbinate on the contralateral side was used as a control.

RESULTS: We identified evidence of bacterial biofilms on the mucosa of all 22 animals under SEM. Twenty-one of 22 animals had sinus cultures positive for Pseudomonas. Bacterial biofilms were identified by evidence of glycocalyx, water channels, and three-dimensional structure. These images were similar to other images of known biofilms.

CONCLUSION: This is evidence of the presence of bacterial biofilms in an animal model of sinusitis. This model may serve as a means to study the efficacy and safety of pharmacologic and surgical treatments on the disruption and elimination of bacterial biofilms. Additional study into the role of bacterial biofilms in perpetuating chronic sinusitis is warranted.