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to reduce the incidence of replacement-associated infections, we developed a novel coatingtechnology of Hydroxyapatite (HA) containing silver (Ag). We reported the Ag-HA coatingshowed high antibacterial activity against E. coli, S. aureus and methicillin-resistant S. aureus(MRSA) under static condition. However, human bodies have a circulating body fluid, which isnot a static condition. And the growth and the maturation of biofilm, which is said that acommon course of persistent infections at a surgical site, are enhanced by the flow of broth inculture environment. Therefore, we evaluated whether the Ag-HA coating inhibits the biofilmformation on its surface or not by a biofilm-forming test under flow condition in this study.Ag-HA or HA powder was sprayed onto the commercial pure titanium disks using a flamespraying system. The HA coating disks were used as negative control. The biofilm-formingmethicillin sensitive S. aureus (BF-MSSA; Seattle 1945) strain and the BF-MRSA (UOEH6)strain were used. The pre-culture bacterial suspension (about 10 5 colony forming units; CFU)was inoculated onto the Ag-HA and HA coating disks. After cultivation at 37 °C for 1 h, thedisks were rinsed twice with 500 µL sterile PBS (−) to eliminate the non-adherent bacteria.The number of the adherent bacteria on these disks was counted using culture method. Afterrinsing, the disks were transferred into petri-dish containing Trypto–Soy Broth (TSB) + 0.25%glucose with a stirring bar on the magnetic stirrer and they were cultured at 37°C for 7 days. Inthe meantime, the stirring bar was spun at 60 rounds per minute. Then, the disks wereimmersed in a fluorescent reagent to stain the biofilm. Finally, the biofilm on each disk wasobserved by a fluorescence microscope and the biofilm-covered rate on the surfaces of themwas calculated using the NIH image software.The number of the bacteria on these disks was not so different between Ag-HA and HA coatingafter rinsing. After biofilm-forming test, the coverage of the biofilm of BF-MSSA was 2.1%and 81.0% on the Ag-HA and HA coatings, respectively. Similarly, in the case of BF-MRSA,it was 7.7% and 72.0% on the Ag-HA and HA coatings, respectively. Though bacteria slightlyadhered, biofilm was hardly observed on the Ag-HA coating. The biofilm on the HA coatingwas extensive and mature. The inhibition effect of biofilm formation on the Ag-HA coatingmight be ascribed to the antibacterial effect by Ag ions released from the coating. Because Agions have a broad spectrum of antibacterial activity against pathogens, including biofilmforming bacteria, they inhibited the biofilm formation on the Ag-HA coating by killing adherentbacteria. Even in a flow condition, it was suggested that the AgHA shows the antibacterialactivity, though the conditions in this work are different from those in living body.Thursday, October 7, 2010, 16:30-17:20Session A8: Periprosthetic Fractures in THAMetal on Metal Total Hip Arthroplasty After Fracture of the Acetabulum*Mohammed Kamal Asal - ? - ?, ?*Email: aymanbassiony@yahoo.comFracture of the acetabulum can lead to degenerative arthritis of the hip, avascular necrosis of thefemoral head, or both. Total hip arthroplasty is a common form of surgical treatment whensignificant joint changes and pain are present.file:///E|/ISTA2010-Abstracts.htm[12/7/2011 3:15:47 PM]