Effects Of The Helical Peptides On Staphylococcus Aureus Biofilm Research

Bacterial biofilm is a kind of complex bacterial colonies and in the colonies bacteria is packaged in extracellular polymers（EPS）secreted by themselves.After bacteria formed biofilm,this special structure allows bacterial resistance to traditional antibiotics and antibacterial agents.Staphylococcus aureus biofilm including extracellular polysaccharide,protein,DNA were removed mainly by using traditional single antibiotic or combination antibiotics.However the antibiotics usually caused bacterial drug resistance and the generation of"superbacteria".Therefore,the highly efficient and low toxicity antibacterial agents against staphylococcus aureus biofilm are in great needed.We tested the antibacterial and anti-biofilm activity of G（IIKK）_3-4I-NH₂ against staphylococcus aureus.As well as its analysis（GA（IIKK）₃I-NH₂,AA（IIKK）₃I-NH₂ and G（IIKK）₃I-NH₂）.The toxicities to normal cells were also tested by using NIH3T3 and red blood cells.The results shared that:（1）G（IIKK）₃I-NH₂ and G（IIKK）₄I-NH₂ had high antibacterial activity aganist staphylococcus aureus,and the minimum inhibitory concentration（MIC）is 8μM and 6μM respectively.（2）G（IIKK）₃I-NH₂ and G（IIKK）₄I-NH₂ can inhibit the formation of staphylococcus aureus biofilm of MIC and 2 MIC respectively.（3）Staphylococcus aureus biofilm formation by inhibiting the initial adherence on the surface.（4）G（IIKK）₃I-NH₂ and G（IIKK）₄I-NH₂ destroyed mature staphylococcus aureus biofilm.They almost can completely destroy mature staphylococcus aureus biofilm formed in CDC bioreactor by killing staphylococcus aureus in the surface and internal of staphylococcus aureus biofilm.In our study,designed efficient antibacterial and anti-biofilm agents,G（IIKK）₃I-NH₂and G（IIKK）₄I-NH₂ which can kill planktonic bacteria,inhibit the formation of staphylococcus aureus biofilm and destroy mature staphylococcus aureus biofilm.Our research provide theory support for further understanding the mechanism of anti-biofilm and at the same time offer new ideals for anti-biofilm peptide designing.