Stigmurin derivatives as potent-biofilm eradicating agents against the major human opportunistic pathogen Pseudomonas aeruginosa

Pseudomonas aeruginosa is a versatile opportunistic pathogen whose capacity to form biofilms contributes to persistent and difficult-to-treat infections, particularly in clinical environments. Conventional antibiotics often fail to eliminate biofilm-embedded bacteria, highlighting the need for alternative therapeutic strategies. Here, we investigated the anti-biofilm activity of Stigmurin, an antimicrobial peptide identified in the venom of Tityus stigmurus , together with six lysine-enriched analogs. The peptides were synthesized and characterized at a physicochemical level, and their effects on bacterial growth, biofilm development, and disruption of pre-established biofilms were evaluated under both static and dynamic conditions. Their influence on pyocyanin production, membrane fluidity, and the tridimensional structure of the most active analog, StigA31, was also analyzed. The peptides revealed no marked impact on bacterial growth or biofilm formation. However, several of them were able to disrupt mature biofilms on polystyrene pegs. Stigmurin (24 h exposition) reduced biofilm biomass by nearly 47%, while StigA31 achieved dispersal levels of up to 35%, even at nanomolar concentrations. Under dynamic flow conditions, both peptides strongly reduced biofilm biovolume and thickness within 2 h and altered matrix exopolysaccharide detection. None of the compounds stimulated pyocyanin production. Stigmurin altered membrane fluidity, whereas StigA31 displayed a distinct mechanism that may be associated with its helical conformation. These findings indicate that Stigmurin analogs, particularly StigA31, promote P. aeruginosa biofilm dispersal through non-bactericidal mechanisms. Their activity at sub-inhibitory concentrations highlights their potential as promising candidates for use in strategies aimed at controlling biofilm-associated infections.