The Inhibition Effect Of Baicalein Against Staphylococcus Aureus Biofilm Formation And Its Mechanism

Staphylococcus aureus is an important pathogen that cause difficulty in treatment or incurable disease because of the biofilm formation when stick on medical equipment, human tissues and organs. Thus looking for a new type of efficient new drugs is an urgent problem to be solved. This study commited to study the inhibition effect of Baicalein against Staphylococcus aureus biofilm formation and its mechanism.The results are as follows:(1) This study used Congo red agar plate method and Crystal violet semi-quantitative method screened for good ability of biofilm formation Staphylococcus aureus(26112);(2) By Crystal violet semi-quantitative method and optical microscope observe the process of biofilm formation.The result indicated that it will take three days to form mature biofilm;(3) By TTC method and agar plate assay to investigate the effects of Baicalein against Staphylococcus aureus biofilm formation. The results show that 0.04mg/ml Baicalein could inhibit the formation of Staphylococcus aureus;The minimal bactericidal concentration was 0.04mg/ml too;(4) TTC method was used to investigate the effects of Baicalein against mature biofilm, the result showed that Baicalein can’t kill the bacterias in the biofilm but make mature biofilm thinner.Then tested the effect of Baicalein against mature biofilm with Ciprofloxacin, the result indicated that 0.12ml/ml Baicalein and 0.64ug/ml Ciprofloxacin could kill the bacterias in biofilm;(5) The result of Dot-blot indicated that Baicalein could inhibit the formation of PIA in biofilm;(6) The detection of eDNA by Micro-Ultraviolet Spectrophotometer showed that Baicalein could inhibit the release of eDNA by 0.04mg/ml, and eDNA reduced by 97%;(7) The influence for Baicalein on icaA and cidA gene expression was detected by RP- PCR method. The results showed that 0.02 mg/ml could inhibite the expression of icaA and cidA(p<0.01).