The LL۳۷-rIb-AMP۴ antimicrobial peptide as a treatment for systematic infection of Pseudomonas aeruginosa, Acinetobacter baumannii, Methicillin-resistant Staphylococcus aureus (MRSA) and Vancomycin-resistant Enterococci (VRE) cells in a mouse model.

Aims: Antimicrobial peptides (AMPs) are beneficial compounds that could be used as a new and effective method to suppress microbes. Both Ib-AMP۴ and LL۳۷ are antimicrobial peptides with a wide range of antimicrobial activities. This research aimed to evaluate the antibacterial potential of LL۳۷-rIb-AMP۴ hybrid protein as an antimicrobial agent against pathogenic bacteria. Therefore, its antibacterial effects against Acinetobacter baumannii, Pseudomonas aeruginosa, vancomycin-resistant Enterococcus (VRE), and methicillin-resistant Staphylococcus aureus (MRSA) were investigated in vivo and in vitro. Materials & Methods: In this study, antimicrobial peptides rIb-AMP۴, LL۳۷, and LL۳۷-rIb-AMP۴ were expressed, purified, and refolded, and their synergistic and antibacterial effects in combination with each other (LL۳۷+rIb-AMP۴) and as fusion proteins (LL۳۷-rIb-AMP۴) were tested against A. baumannii, P. aeruginosa, VRE, and MRSA cells in vitro (MIC, time kill, and SEM) and against P. aeruginosa and VRE cells in vivo. Findings: LL۳۷-rIb-AMP۴ Protein with molecular weight= ۲۸ KD was correctly produced and purified. Despite the lack of synergistic effects between LL۳۷ and rIb-AMP۴ peptides in vitro, the stability test results showed higher stability for LL۳۷-rIb-AMP۴ hybrid protein. The findings of in vivo tests confirmed that all infected mice were improved with LL۳۷-rIb-AMP۴ and no signs of bacteria were observed in their blood and spleen samples. Also, these results confirmed the stability and higher activity of LL۳۷-rIb-AMP۴ than the single form of these proteins. Conclusion: Considering the antimicrobial potential of the produced proteins, it seems that the recombinant LL۳۷-rIb-AMP۴ protein could be considered and used as a stable and active antimicrobial drug in future studies.

کلیدواژه ها:

Antimicrobial peptides ، Hybrid protein ، LL۳۷ peptide ، rIb-AMP۴ peptide