ABSTRACT
OBJECTIVE To establish the implanted biofilm model of rabbit implant infection.METHODS SEP was cultured,purified,identified,and tested for the drug sensitivity and the biofilm production.Healthy adult rabbits were randomly divided into 4 groups,8 in each group.The stainless steel screws and washer UHMWPEs were implanted into the femoral condyle of the non-articular surface of the rabbit right stifle knee.The knee joints were inoculated with 1ml sterile saline,102,103 and 104 CFU SEP,respectively.Wounds were observed postoperatively.After the 14th days postoperation,the knee synovium of 32 rabbits sacrificed were taken out by aseptic technique and were cultured to determine whether the knees were infected and which concentration of SEP was the appropriate for causing knee joint infection.UHMWPEs from the appropriate ID group were observed to find whether there were biofilms on the surface by SEM and LCSM.RESULTS The bacterial strain was identified as SEP and could produce biofilm.Among the knee joints inoculated with 1ml saline,102,103 and 104 CFU SEP,the infective rate was 0,37.5%,100.0% and 100.0% and poor wound healing was in 0,1,2 and 4 rabbits,respectively.It showed 103 CFU of SEP was the appropriate ID.Biofilms were found on all UHMWPE surfaces from 103 CFU SEP group by SEM and LCSM.SEM showed SEP in the biofilms on the surface of UHMWPE was agglomerated and wrapped in the matrix.The structure of biofilms in which SEP radiated red fluorescence was inlaid in mucopolysaccharide stained green fluorescence was observed by LCSM.CONCLUSIONS The model provides an effective method to investigate the biofilm.