Agata Lesiak

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.

The usage of nanotechnology in the fight against parasitic diseases is in the early stages of development, but it brings hopes that this new field will provide a solution to target the early stages of parasitosis, compensate for the lack of vaccines for most parasitic diseases, and also provide new treatment options for diseases in which parasites show increased resistance to current drugs. The huge physicochemical diversity of nanomaterials developed so far, mainly for antibacterial and anti-cancer therapies, requires additional studies to determine their antiparasitic potential. When designing metallic nanoparticles (MeNPs) and specific nanosystems, such as complexes of MeNPs, with the shell of attached drugs, several physicochemical properties need to be considered. The most important are: size, shape, surface charge, type of surfactants that control their dispersion, and shell molecules that should assure specific molecular interaction with targeted molecules of parasites’ cells. Therefore, it can be expected that the development of antiparasitic drugs using strategies provided by nanotechnology and the use of nanomaterials for diagnostic purposes will soon provide new and effective methods of antiparasitic therapy and effective diagnostic tools that will improve the prevention and reduce the morbidity and mortality caused by these diseases.

Background: Stenotrophomonas maltophilia (S. maltophilia) is an emerging opportunistic Gram-negative rod causing nosocomial infections predominantly in immunocompromised patients. Due to its broad intrinsic resistance to antibiotics, including carbapenems and the ability to form a biofilm, it is difficult to eradicate. Methods: In this study, the benefit of combined administration (potential synergism) and anti-biofilm activity of ceragenins: CSA-13, CSA-44, and CSA-131 (synthetic mimics of natural antimicrobial peptides) with ceftazidime, levofloxacin, co-trimoxazole and colistin against clinical strains of S. maltophilia were determined using MIC/MBC (minimum inhibitory concentration/minimum bactericidal concentration), killing assays and CV staining. Results: Obtained data indicate that the ceragenins exhibit strong activity against the tested strains of S. maltophilia grown in planktonic culture and as stationary biofilms. Moreover, with some strains, the synergy of ceragenins with conventional antibiotics was observed Conclusion: Our data suggest that ceragenins are promising agents for future development of new methods for treatment of infections caused by S. maltophilia, along with its potential use in combination with conventional antibiotics.