In Silico Design,Synthesis, and In Vitro Evaluation of Novel Amphipathic Short Linear Peptides Against Clinically Relevant Bacterial Biofilms

Microbial biofilms are organized communities of cells that are associated with a wide spectrum of resistant and chronic infections that lead to the treatment failure. Accordingly, there is an urgent demand to create novel effective therapeutic drugs that can inhibit biofilm formation with new mechanisms of action to surmount the current escalating resistance. In this study, in silico hybrid model was utilized to develop three novel short linear peptides (4, 5, and 6) with potential biofilm inhibiting activities (scores?>?1.0). The peptides were composed of cationic and hydrophobic residues. They were synthesized using solid-phase strategy. Synthesized peptides were purified and characterized by reverse-phase high-performance liquid chromatography and matrix-assisted laser desorption/ionization spectroscopy, respectively. They were evaluated using in vitro assay as potential inhibitors of clinically relevant Gram-positive and Gram-negative biofilms. Peptide (4) with five positive charges at physiological pH (4 cationic moieties and W:R?=?1:4) showed activity against biofilms of Gram-positive strains (Staphylococcus epidermidis and Listeria monocytogenes). On the other hand, peptide (5) with six positive charges (5 cationic moieties and W:R?=?2:2) demonstrated activity against Gram-positive (S. epidermidis) and Gram-negative (Escherichia coli) biofilms. Interestingly, peptide (6), with seven positive charges (6 cationic moieties and W:R?=?2:5) revealed higher and broader spectrum of activity against biofilms of Gram-positive (S. epidermidis, S. aureus, L. monocytogenes) and Gram-negative (E. coli).