The antibacterial activity and mechanism of a novel peptide MR-22 against multidrug-resistant .

Introduction: Bacterial infections have become serious threats to human health, and the excessive use of antibiotics has led to the emergence of multidrug-resistant (MDR) bacteria. is a human bacterial pathogen, which can cause severe infectious. Antimicrobial peptides are considered the most promising alternative to traditional antibiotics.

Materials And Methods: The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and hemolytic activity were determined by the microdilution method. The antimicrobial kinetics of MR-22 against were studied by growth curves and time-killing curves. The cytotoxicity of MR-22 was detected by the CCK-8 assay. The antimicrobial activity of MR-22 in salt, serum, heat and trypsin was determined by the microdilution method. The antimicrobial mechanism of MR-22 against drug-resistant was studied by Scanning Electron Microscope, laser confocal microscopy, and Flow Cytometry. The antibacterial activity of MR-22 was evaluated by the mice model of peritonitis.

Results And Discussion: In this study, MR-22 is a new antimicrobial peptide with good activity that has demonstrated against MDR . The antimicrobial activity of MR-22 exhibited stability under conditions of high temperature, 10% FBS, and Ca. However, a decline of the activity was observed in the presence of Na, serum, and trypsin. MR-22 had no significant cytotoxicity or hemolysis . SEM and fluorescent images revealed that MR-22 could disrupt the integrity of cell membrane. DCFH-DA indicated that MR-22 increased the content of reactive oxygen species, while it decreased the content of intracellular ATP. In mice model of peritonitis, MR-22 exhibited potent antibacterial activity . These results indicated that MR-22 is a potential drug candidate against drug-resistant .