Ensuring proper dental hygiene is of paramount importance for individuals’ general well-being, particularly for patients receiving medical care. There is a prevailing utilization of conventional oral hygiene items, including toothbrushes and mouthwashes, which have gained widespread acceptance; nevertheless, their limitations encourage investigating novel options in this domain. Our study indicates that ceragenins (CSAs) being lipid analogs of host defense peptides, well-recognized for their wide-ranging antimicrobial properties, may be a potentially efficacious means to augment oral hygiene in hospitalized individuals. We demonstrate that ceragenins CSA-13, CSA-44, and CSA-131 as well as undescribed to date CSA-255 display potent antimicrobial activities against isolates of fungi, aerobic, and anaerobic bacteria from Candida, Streptococcus, Enterococcus, and Bacteroides species, which are well-recognized representatives of microbes found in the oral cavity. These effects were further confirmed against mono- and dual-species fungal and bacterial biofilms. While the ceragenins showed similar or slightly diminished efficacy compared to commercially available mouthwashes, they demonstrated a highly favorable toxicity profile toward host cells, that may translate into better maintenance of host mucosal membrane stability. This suggests that incorporating ceragenins into oral hygiene products could be a valuable strategy for reducing the risk of both oral cavity-localized and secondary systemic infections and for improving the overall health outcomes of individuals receiving medical treatment.

Background/Objectives: Ceragenins (CSAs) maintain strong antibacterial activity even in cystic fibrosis (CF) sputum. Ivacaftor (IVA), a CF transmembrane regulator modulator, provides significant clinical benefits in CF therapy. Based on these properties, we hypothesized that the combination of CSAs and IVA, due to their antibacterial and biofilm-penetrating abilities, may also be beneficial in the treatment of chronic rhinosinusitis (CRS), including CRS in CF patients. Notably, the physicochemical properties of biofilms in chronic rhinosinusitis (CRS) resemble those in CF sputum. Methods: We determined the minimal inhibitory and bactericidal concentrations (MIC and MBC) and the fractional inhibitory concentration index (FICI) for ceragenins (CSA-13, CSA-44, CSA-131), ivacaftor (IVA), selected conventional antibiotics, and their combinations against both reference and clinical strains. Bacterial viability within biofilms was also evaluated following exposure to these agents. Atomic force microscopy (AFM) was used to analyze the morphology and nanomechanical properties of Staphylococcus aureus and Pseudomonas aeruginosa. In addition, rheological measurements of Pseudomonas aeruginosa biofilms treated with CSAs combined with IVA were performed using a rotational rheometer. Results: The tested agents demonstrated anti-biofilm activity against bacterial strains associated with CRS development. IVA enhanced the anti-biofilm effects of both CSAs and tested antibiotics. CSAs exhibited low MIC and MBC values, confirming their efficacy against tested pathogens. AFM showed that CSA-44, IVA, vancomycin, and their combinations altered the nanomechanical properties of Pseudomonas aeruginosa and Staphylococcus aureus cells. Interestingly, the addition of IVA induced aggregation of S. aureus cells. CSAs reduced the stiffness of P. aeruginosa biofilms, and co-treatment with IVA resulted in a further decrease in biofilm stiffness. Conclusions: These findings indicate that ceragenins, particularly in combination with ivacaftor, represent a promising therapeutic strategy for challenging chronic infections caused by the studied bacteria. This supports further research aimed at developing new treatment methods for CRS.