Anaerobic bacteria growth in the presence of cathelicidin LL-37 and selected ceragenins delivered as magnetic nanoparticles cargo

Background: Cationic antibacterial peptides (CAPs) and synthetic molecules mimicking the amphiphilic structure of CAPs, such as ceragenins, are promising compounds for the development of new antimicrobials. Results: We tested the in vitro activity of ceragenins CSA-13 and CSA-131 against several anaerobic bacteria including Bacteroides spp. and Clostridium difficile. We compared results to the activity of cathelicidin LL-37, metronidazole and nanosystems developed by attachment of CSA-13 and CSA-131 to magnetic nanoparticles (MNPs). The antibacterial effect was tested using killing assay and modified CLSI broth microdilution assay. Ceragenins CSA-13 and CSA-131 displayed stronger bactericidal activity than LL-37 or metronidazole against all of the tested bacterial strains. Additionally CSA-131 revealed an enhanced ability to prevent the formation of Bacteroides fragilis and Propionibacterium acnes biofilms. Conclusions: These data confirmed that ceragenins display antimicrobial activity against a broad range of microorganisms including anaerobic bacteria and deserve further investigations as compounds serving to develop new treatment against anaerobic and mixed infections.