Evaluation of Antibacterial Activity of cLFchimera and its Synergistic Potential with Vancomycin against Methicillin-Resistant Staphylococcus aureus

Frequent and unlimited use of antibiotics caused the development of antibiotic resistance by microorganisms. Therefore, there is an urgent need to discover novel antibacterial agents or a combination of agents as a safe treatment strategy for various infections. In the present study, the synergistic effects of cLFchimera, an antimicrobial peptide, and the vancomycin antibiotic were evaluated using the checkerboard method against methicillin-Resistant Staphylococcus aureus (MRSA) bacteria strain. cLFchimera had antimicrobial activity against MRSA and methicillin-sensitive Staphylococcus aureus (MSSA) (MIC: 256 and 512 μg/mL, respectively). A synergistic effect was observed in the combination of cLFchimera with vancomycin (FIC: 0.375). The results showed that at FIC concentrations, the release of cytoplasmic materials from bacterial cells and the number of surviving cells were significantly (p ≤ 0.05) higher and lower, respectively, than when peptides or antibiotics were used alone. SEM electron microscopic analysis at FIC concentration showed severe membrane damage of bacterial cells. In conclusion, the use of cLFchimera and vancomycin at FIC concentration reduces the consumption of both substances.