Comparative effects of saline, streptomycin, and ozone nasal irrigation on Staphylococcus aureus-induced experimental rhinosinusitis: microbiological, histopathological, and biofilm analyses

Objective Rhinosinusitis is characterized by inflammation of the nasal mucosa and paranasal sinuses. Nasal irrigation is widely used as an adjunctive treatment for sinonasal diseases. The aim of this study was to evaluate whether nasal irrigation with streptomycin or ozone provides additional benefit compared with saline irrigation alone.Methods We used 22 female Sprague-Dawley rats to induce bacterial rhinosinusitis. Group 1 was not irrigated, group 2 was irrigated with saline, group 3 with streptomycin, and group 4 with ozone solution. After the treatment, sinus mucosa samples were evaluated using microbiological methods to measure bacterial load. The histopathological inflammation rate was determined, and biofilm formation was assessed semi-quantitatively using scanning electron microscopy.Results After irrigation, a significant reduction in bacterial counts was observed in all groups. In the streptomycin group, viable bacteria in the lumen were largely reduced; however, bacteria that adhered to the mucosa remained. Although the streptomycin group showed the lowest average scores for both biofilm and inflammation, these differences were not statistically significant. Overall, there was no statistically significant difference between the groups.Conclusions This experimental study explored biofilm formation in an acute bacterial rhinosinusitis model. Irrigation procedures were associated with a reduction in bacterial load, but no statistically significant differences were observed between groups in terms of histopathological findings or biofilm formation. These findings should be interpreted cautiously, and further studies with larger sample sizes are required to clarify their potential clinical relevance.Levels of evidence Not applicable (preclinical animal model).