Nature-inspired designing of KLR- and KLS-rich antimicrobial peptides: unleashing the antibiofilm potential of RbP12 against MDR S. aureus and P. aeruginosa.

Objectives: Biofilm formation is a mechanism exhibited by bacteria, making them 10-1000 times more resistant than planktonic cells. The aim was to collect the most suitable characteristics from already available antibiofilm peptides and design novel antibiofilm peptide sequences along with these characteristics altogether in one sequence.

Methods: Antibiofilm peptides were collected from AMP database (APD3), and sequence analysis was performed to derive the most suitable features. An artificial design approach, modified database filtering technology, was chosen to design novel peptide sequences, and their activity was predicted by machine-learning prediction models. Antibacterial and antibiofilm potential of the selected peptide sequence (arginine-based peptide 12; RbP12) was assessed against Staphylococcus aureus P10 and Pseudomonas aeruginosa PA64.

Results: A total of 34 peptides were designed, of which 22 were arginine based and 12 were serine based. All the designed peptides were predicted to have antibiofilm properties. RbP12 was found to inhibit the growth of S. aureus P10 completely at an MIC of 85 mg/L, while the percentage inhibition of P. aeruginosa PA64 was calculated to be 32.1%. Significant inhibition of biofilms by RbP12 was observed in the case of both S. aureus P10 and P. aeruginosa PA64. An MTT assay showed no significant cytotoxicity by RbP12 with 96% cell viability.

Conclusions: RbP12 was found to have higher antibacterial and antibiofilm activity against S. aureus P10 compared with P. aeruginosa PA64. With 96% cell viability, usage of RbP12 on human skin is totally safe. Based on these results, the aim is to develop self-assembled peptide hydrogels for wound healing in future work.