Intracellular bactericidal activity of MDP1 antimicrobial peptide against VRSA and MRSA in human endothelial cells

Abstract

Abstract Background Staphylococcus aureus (S. aureus) acts as a major causative agent of postoperative infections by thriving within host cells leading to persistent and chronic infections. The limited efficacy of conventional antibiotics against intracellular S. aureus is attributed to their inability to penetrate host cells. In this study, we evaluated a cell-penetrating peptide, MDP1, which was derived from melittin for the purpose of eliminating S. aureus. This study aimed to assess the bactericidal effectiveness of the cationic antimicrobial peptide MDP1 against intracellular S. aureus. S. aureus infection model was employed to evaluate MDP1's efficacy in eliminating intracellular S. aureus. Methods The most pathogenic clinical isolates of Vancomycin- and Methicillin-resistant S. aureus (VRSA and MRSA) which express high level of fibronectin binding protein A were selected by real-time PCR. Internalization of the bacteria into endothelial cell model was proved by culture and transmission electron microscopy (TEM). Results In vitro assessments revealed potent antibacterial characteristics, indicating that MDP1 is efficacious in eliminating intracellular VRSA and MRSA in the cells; proved by culture and fluorescent microscopy. Conclusions These findings indicate that the innovative MDP1 antimicrobial peptide could serve as a viable therapeutic for eradication of intracellular bacterial infections. Our results suggest that more novel approaches to targeted therapy might be developed by the targeting of antimicrobial peptides to endothelial receptor.