ObjectiveTo study and compare the bactericidal effect of E. coli OmpA signal peptide-derived peptide P-KKK on different bacteria in vitro. MethodsThe bactericidal activity of the derived peptide P-KKK against gram-positive (G+) and gram-negative (G-) bacteria was determined by agar plate count method. Different concentrations of the derivatized peptide P-KKK were compared with the three G+ bacterium (Staphylococcus aureus, Enterococcus faecium, Bacillus subtilis) and three G- bacteria (E. coli, Klebsiella pneumoniae, Pseudomonas aeruginosa) incubate at 37℃ for 2h. After plating, the cells were incubated at 37℃ for 18 h to 24 h. The amount of colony formation (CFU) on each agar plate was recorded and the bactericidal rate of the peptide P-KKK was calculated. ResultsThe derived peptide P-KKK has a strong bactericidal activity against G+ bacteria. When the concentration is 200 ug/mL, it can kill more than 98.5% of G+ bacteria. The sterilization rate reaches 80.2% when the concentration is 40ug/mL, it also has strong bactericidal activity against G- bacteria. At a concentration of 200 ug/mL, more than 93.8% of the G- bacteria can be killed. When the concentration is 40 ug/mL, the sterilization rate also reaches 15.2% to 99.7%. ConclusionE. coli OmpA signal peptide-derived peptide P-KKK has significant bactericidal activity against both G+ and G- bacteria. Further research on its structure and function will help develop new antibacterial drugs.

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