© 2012 Wichtig Editore - ISSN 0391-3988 Int J Artif Organs ( 2012; : 00) 000-000 00 1 Influence of prophylactic antibiotics on tissue integration versus bacterial colonization on poly(methyl methacrylate) Guruprakash Subbiahdoss, Thomas Aleyt, Roel Kuijer, Henk J. Busscher, Henny C. van der Mei Department of Biomedical Engineering, University Medical Center Groningen, Groningen and University of Groningen, Groningen - The Netherlands ABSTRACT Purpose: Biomaterial-associated infections (BAI) remain a major concern in modern health care. BAI is difficult to treat and often results in implant replacement or removal. Pathogens can be introduced on implant surfaces during surgery and compete with host cells attempting to integrate the implant. Here we studied the influence of prophylactically given cephatholin in the competition between highly viru- lent Staphylococcus aureus and human osteoblast-like cells (U-2 OS, ATCC HTB-94) for a poly(methyl methacrylate) surface in vitro using a peri-operative contamination model. Method: S. aureus was seeded on the acrylic surface in a parallel plate flow chamber prior to adhe- sion of U-2 OS cells. Next, S. aureus and U-2 OS cells were allowed to grow simultaneously under shear (0.14 1/s) in a modified culture medium containing cephatholin for 8 h, the time period this drug is supposed to be active in situ. Subsequently, the flow was continued with modified culture medium for another 64 h. Results: In the absence of cephatholin, highly virulent S. aureus caused U-2 OS cell death within 18 h. In contrast, the presence of cephatholin for 8 h resulted in survival of U-2 OS cell up to 72 h during simultaneous growth of U-2 OS cells and bacteria. Not all adhering bacteria were killed however, but they showed a delayed growth. Conclusions: These findings are in line with the recalcitrance of biofilms against antibiotic treatment observed clinically, and represent another support for the use of in vitro co-culture models in mimick- ing the clinical situation. KEY WORDS: Biomaterial-associated infection, Race for the surface, S. aureus, Biomaterials, Antibiotics, Biofilm Accepted: August 17, 2012 ORIGINAL ARTICLE DOI: 10.5301/ijao.5000155 INTRODUCTION Biomaterial-associated infections (BAI) are a major prob- lem in modern medicine. BAI is often difficult to treat, as the biofilm mode of growth protects infecting pathogens against both the host defense system and antibiotics (1). In most cases, the final remedy of a BAI is removal of the implant associated with the infection. Bacterial contamina- tion of biomaterial implants during the surgical procedure (peri-operative contamination) is the most common route of contamination. Whether or not infection develops de- pends on the outcome of the so-called “race for the sur- face” between successful tissue integration of the implant surface and colonization of the surface by pathogens (2). If this race is won by tissue cells, then the implant sur- face is covered by a cellular layer and is less vulnerable