In vitro Nasodine Can be an Effective Antibiofilm Agent for Biofilms that May Cause CRS

Abstract

ObjectivesBacterial biofilms on the sinonasal mucosa, especially biofilms of Staphylococcus aureus, are associated with greater severity and recalcitrance of chronic rhinosinusitis (CRS). There are few, if any, antibiofilm agents suitable for sinonasal application available for the management of this problem. Nasodine® Nasal Spray (Nasodine) is a 0.5% povidone‐iodine‐based formulation that has been developed for sinonasal application. We investigated the antibiofilm efficacy of Nasodine to determine whether it may be a candidate for the treatment of biofilm‐associated CRS.MethodsBiofilms of S. aureus ATCC 6538 were grown in vitro using the Centers for Disease Control biofilm reactor. Intact biofilms were treated by immersion in 0.9% saline (control), half concentration Nasodine, or full concentration Nasodine for between 5 min and 6 h. Further biofilm cells were dispersed into suspension then treated for between 30 s and 5 min. Surviving bacteria were then enumerated by culture and counting colonies, and the log10 reduction in viable bacteria was compared with control.ResultsNasodine demonstrated time and concentration‐dependent bacterial killing against intact biofilm. Statistically significant reductions in viable bacteria from intact biofilms were seen with exposures as brief as 5 min. Nasodine consistently eradicated dispersed biofilm within 1 min.ConclusionNasodine is highly active against biofilms of S. aureus ATCC 6538 in vitro. Biofilm killing is impeded by the presence of the intact biofilm structure.Lay summary:In chronic rhinosinusitis (CRS), bacterial communities called biofilms are associated with more severe inflammation. An iodine‐based nasal spray called Nasodine almost completely eradicates bacterial biofilms after 6 h of exposure. Nasodine may be useful for treating CRS. Laryngoscope, 133:2490–2495, 2023