Department of Biomedical Engineering, University Medical Center Groningen and University of Groningen, PO Box 196, 9700 AD Groningen, The Netherlands.
Microbiology (Reading). 2010 Oct;156(Pt 10):3073-3078. doi: 10.1099/mic.0.040378-0. Epub 2010 Jul 1.
Biomaterial-associated infections are the major cause of implant failure and can develop many years after implantation. Success or failure of an implant depends on the balance between host tissue integration and bacterial colonization. Here, we describe a new in vitro model for the post-operative bacterial contamination of implant surfaces and investigate the effects of contamination on the balance between mammalian cell growth and bacterial biofilm formation. U2OS osteosarcoma cells were seeded on poly(methyl methacrylate) in different densities and allowed to grow for 24 h in a parallel-plate flow chamber at a low shear rate (0.14 s(-1)), followed by contamination with Staphylococcus epidermidis ATCC 35983 at a shear rate of 11 s(-1). The U2OS cells and staphylococci were allowed to grow simultaneously for another 24 h under low-shear conditions (0.14 s(-1)). Mammalian cell growth was severely impaired when the bacteria were introduced to surfaces with a low initial cell density (2.5 × 10(4) cells cm(-2)), but in the presence of higher initial cell densities (8.2 × 10(4) cells cm(-2) and 17 × 10(4) cells cm(-2)), contaminating staphylococci did not affect cell growth. This study is believed to be the first to show that a critical coverage by mammalian cells is needed to effectively protect a biomaterial implant against contaminating bacteria.
生物材料相关感染是植入物失败的主要原因，并且可能在植入物后多年发生。植入物的成功或失败取决于宿主组织整合和细菌定植之间的平衡。在这里，我们描述了一种新的体外模型，用于研究植入物表面术后细菌污染，并研究污染对哺乳动物细胞生长和细菌生物膜形成之间平衡的影响。将 U2OS 骨肉瘤细胞以不同密度接种在聚甲基丙烯酸甲酯上，并在低剪切率（0.14 s(-1))下在平行板流动室中培养 24 h，然后以 11 s(-1)的剪切率用表皮葡萄球菌 ATCC 35983 污染。在低剪切条件（0.14 s(-1))下，允许 U2OS 细胞和葡萄球菌同时再生长 24 h。当细菌引入初始细胞密度较低（2.5 × 10(4) 个细胞 cm(-2))的表面时，哺乳动物细胞的生长受到严重抑制，但在初始细胞密度较高（8.2 × 10(4) 个细胞 cm(-2)和 17 × 10(4) 个细胞 cm(-2))时，污染的葡萄球菌不会影响细胞生长。这项研究据信是首次表明，需要哺乳动物细胞的临界覆盖才能有效地保护生物材料植入物免受污染细菌的侵害。
