In-vitro Study On The Evolution Of Staphylococcus Aureus Bacteria Biofilm On The Surface Of Titanium Alloy And The Antibacterial Activity Of Iodophor

Objective:(1)To observe the changes of the morphological structure of the bacterial biofilm of Staphylococcus aureus bacteria on the surface of titanium alloy in four different time periods in one month through confocal laser scanning microscopy(CLSM)and scanning electron microscopy(SEM).(2)To evaluate the antibacterial activity of 0.5% povidone-iodine on biofilm bacteria in 4 different time periods within one month.(3)To provide biofilm-related visualization of relevant infections with clinical implants and to provide guidance on treatment-related solutions.Method:(1)Standard Staphylococcus aureus bacteria biofilms of 1 week,2 weeks,3 weeks and 4 weeks were established on the surface of clinical titanium alloy and the biofilm morphology were detected by the confocal laser scanning microscope and scanning electron microscope.(2)Each time period was divided into 3 groups one other deal with PBS and the others with 0.5 % Povidone-iodine soaking for 5min and 10 min in order to observe the antimicrobial activity of Povidone iodine on the bacteria in the culture of Staphylococcus aureus biofilm cultured at different times and to know the effect of iodophor by the viable counting.Result:(1)With the prolongation of culture time,the extracellular polymer of the Staphylococcus aureus biofilm continued to accumulate,the number of layers increased,and the spatial structure of biofilm became mature.The changes were more obvious at the third week,and the biofilm became mature and stable at the fourth week.(2)0.5%Povidone iodine had a good bactericidal effect on the bacteria in the biofilm,0.5%povidone–iodine sterilization ten minutes was better than zero minutes(P<0.05)and 0.5%povidone–iodine sterilization five minutes was better than zero minutes(P<0.05),the bactericidal effect of the povidone-iodine was more significant after extending soaking time.With the prolongation of biofilm incubation,however,the effect of povidone iodine was weakened,but the effect of 10 min was better than that of 5 min.Yet povidone iodine could not completely kill the bacteria in the biofilm.Conclusions:(1)The maturation of the biofilm is bacteria and outside then formation of extracellular polymeric substance and they formation micro environment together and slowly secretes extracellular polymers.With the extension of incubation time,the polymer matures and forms a certain spatial structure.Finally,the bacteria and their secreted extracellular polymers together form a mature and stable microenvironment,that is,a mature bacterial biofilm.(2)The boundary of early biofilm and the mature biofilm lies at the third week.The main difference lies in the maturation of the exopolysaccharide,the increase of the biofilm layer and the maturation and stability of the whole microenvironment of bacteria and biofilm.(3)Early Implant related biofilm 0.5% povidone-iodine effect at 10 min is better than that of 5min,but there is no extension meaning of statical after maturity.(4)It is suggested that prosthesis could be preserved if the time of relevant infections on clinical implants is less than 3 weeks,and 0.5% povidone-iodine should be used to soak for 10 min after debridement.The effect will be better if antibiotic treatment is combined after operation.(5)Using different combinations of stains to observe the evolution of bacterial biofilm is a reliable and effective method.