Abstract：Objective To study the effects of ε-poly-L-lysine (ε-PL) on the growth and biofilm formation of Staphylococcus aureus (S. aureus). Methods S. aureus standard strain ATCC25923 and community-acquired methicillin-resistant S. aureus (MRSA) USA300 were used as test strains and the constant broth dilution method (test tube) was performed to determine the minimum inhibitory concentration (MIC). The growth curve of S. aureus was observed by spectrophotometry, the formation of biofilm in each strain was detected by 96-well crystal violet dyeing method and biofilm formation was observed with a scanning electron microscope (SEM). Results The MIC of the ε-PL on ATCC25923 and USA300 was 31.25mg/mL. And with the increase of ε-PL concentration, the inhibitory effect on the growth of two strains was gradually enhanced. 1/2 MIC ε-PL can significantly reduce the biofilm formation of ATCC25923 and USA300. Conclusion ε-PL as a safe and efficient natural preservative, significantly inhibited the growth of S. aureus bacteria and biofilm formation, and provided the theoretical basis for the development of new antimicrobial drugs.
