Esculentin-1a Derived Antipseudomonal Peptides: Limited Induction of Resistance and Synergy with Aztreonam

Title:Esculentin-1a Derived Antipseudomonal Peptides: Limited Induction of Resistance and Synergy with Aztreonam

Volume: 25 Issue: 12

Author(s): Bruno Casciaro, Maria Rosa Loffredo, Vincenzo Luca, Walter Verrusio, Mauro Cacciafesta and Maria Luisa Mangoni*

Affiliation:

• Laboratory affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, via degli Apuli, 9, 00185, Rome,Italy

Keywords: Antibiotic resistance, Pseudomonas aeruginosa, synergism, esculentin-1a, cystic fibrosis, aztreonam.

Abstract: Background: The massive use of antibiotics has led to the selection of resistant bacterial strains that are difficult to eradicate. Among these, Pseudomonas aeruginosa most frequently colonizes and infects the airways of cystic fibrosis patients. Cationic Antimicrobial Peptides (AMPs) represent interesting molecules for the development of new antimicrobial agents. Thanks to their mechanism of action that involves the permeabilization of the bacterial cytoplasmic membrane, the induction of resistance is quite limited.

Objective: The evaluation of the capability of two frog-skin derived AMPs, i.e. Esc(1-21) and its diastereomer Esc(1-21)-1c, to induce resistance in P. aeruginosa and synergize with aztreonam.

Method: The induction of resistance was evaluated after 15 cycles of exposure to non-inhibitory growth concentrations of antibiotics and peptides. Subsequently, the Minimal Inhibitory Concentration (MIC) was calculated and compared to that obtained before drug exposure. Furthermore, MICs of AMPs and antibiotics were evaluated in Artificial Sputum Medium (ASM). Finally, the ability of the two peptides to synergize with aztreonam was determined by the checkerboard titration method.

Results: Pseudomonas aeruginosa acquired resistance to antibiotics, as evidenced by the increased MICs compared to the initial ones (from 8 to 128-fold higher), while no change in MICs was observed after multiple treatments with the Esc-peptides. In addition, both peptides showed significantly lower MICs than aztreonam in ASM. Finally, the diastereomer Esc(1-21)-1c had the ability to synergize with aztreonam in inhibiting growth and in killing Pseudomonas cells.

Conclusion: Both peptides represent promising candidates for the development of new antipseudomonal compounds, which do not induce resistance.

Cite this article as:

Casciaro Bruno , Loffredo Rosa Maria , Luca Vincenzo , Verrusio Walter , Cacciafesta Mauro and Mangoni Luisa Maria *, Esculentin-1a Derived Antipseudomonal Peptides: Limited Induction of Resistance and Synergy with Aztreonam, Protein & Peptide Letters 2018; 25 (12) . https://dx.doi.org/10.2174/0929866525666181101104649