Toward the Treatment of Paranasal Sinus Biofilms Using a Novel Nuclease

Abstract

Objective: 1) Characterize the microstructure of paranasal sinus biofilms. 2) Characterize the microbial composition of sinus biofilms. 3) Develop techniques to treat sinus infections by breaking up sinus biofilms using surfactants and a novel, marine derived nuclease.

Method: Sinus biofilms were collected intraoperatively. Microbial composition was investigated by culturing and 16S rDNA sequencing, and the biofilm structure was analyzed by electron microscopy. Duplicate samples were treated with or without the marine nuclease (NucB) at 370C. The effect of NucB was measured by mass reduction before and after treatment.

Results: 16SrDNA analysis demonstrated populations of Staphylococcus aureus, S epidermis, and Kocuria rhizophila. Anaerobic bacteria were recovered in limited numbers, and few fungal strains were observed. Transmission electron microscopy of characteristic tenacious biofilms showed an unusual layered structure. Samples consisted of endogenous mucin-rich layers with occasional pockets of bacterial cells, which were found throughout the biofilm. A commercially available surfactant was used to disperse the upper layers of mucin to allow penetration by the nuclease into the deeper bacterial biofilm. In vitro studies with the nuclease against model organisms also showed effective breakup of biofilms.

Conclusion: We have shown that characteristic tenacious sinus “biofilm” has an unusual microscopic structure. Bacteria appeared to be localized in foci and may have been responsible for stimulating a host response. We are developing methods to remove sinus biofilms using a microbial nuclease that breaks down DNA holding the biofilm together.