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Updated: Aug 16, 2026
In Vitro Assay of Bacterial Adhesion onto Mammalian Epithelial Cells
Published on: May 16, 2011
In vitro adherence and accumulation of Staphylococcus epidermidis RP 62 A and Staphylococcus epidermidis M7 on four
D P König1, J M Schierholz, R D Hilgers
1Department of Orthopaedic Surgery, Cologne University, Joseph Stelzmann Strasse 9, 50924 Köln, Germany. dietmar-pierre.koenig@medizin.uni-koeln.de
Abstract:
Bacterial resistance of Staphylococcus epidermidis, a serious pathogen of implant-related infections, to antibiotics is related to the production of a glycocalyx slime that impairs antibiotic access and the killing by host defense mechanisms. In vitro studies of different bone cements containing antibiotics, developed for the prevention of biomaterial-associated infection, could not always demonstrate complete eradication of biomaterial-adherent bacteria. We have investigated four different bone cements in regard to bacterial accumulation of a slime-producing strain RP 62 A and its isogenic mutant M7 lacking the ability to produce exopolysaccharide slime using a bacterial adhesion assay and modified Kirby-Bauer technique. A significant effect of exopolysaccharide production for the accumulation on bone cement could be demonstrated. The gentamicin/clindamycin bone cement was the only tested biomaterial that produced a large zone of bacterial inhibition in the inoculated area adjacent to the biomaterial. The bacterial adhesion was not reduced significantly and there was no correlation between zones of inhibition on blood agar plates and the quantitative adhesion assay. The clinical efficacy of the gentamicin/clindamycin bone cement must be proven in vivo.
Insights
Slime-producing Staphylococcus epidermidis resists antibiotics via glycocalyx. Gentamicin/clindamycin bone cement showed bacterial inhibition, but clinical efficacy requires further in vivo proof.
Area of Science:
- Biomaterials Science
- Infectious Diseases
- Microbiology
Background:
- Staphylococcus epidermidis causes implant-related infections, often resisting antibiotics due to glycocalyx slime production.
- This slime layer hinders antibiotic penetration and host immune responses.
- Existing antibiotic-loaded bone cements show variable efficacy in eradicating adherent bacteria in vitro.
Purpose of the Study:
- To evaluate the impact of exopolysaccharide (slime) production on Staphylococcus epidermidis adherence to bone cement.
- To compare the efficacy of four different antibiotic-loaded bone cements against a slime-producing strain and its non-slime-producing mutant.
- To assess the correlation between in vitro bacterial adhesion and zones of inhibition.
Main Methods:
- Utilized a bacterial adhesion assay to quantify bacterial accumulation on bone cement.
- Employed a modified Kirby-Bauer technique to assess zones of bacterial inhibition.
- Compared a slime-producing strain (RP 62 A) with its isogenic mutant (M7) lacking exopolysaccharide production.
Main Results:
- Exopolysaccharide production significantly influenced bacterial accumulation on bone cement.
- Gentamicin/clindamycin bone cement was the only material demonstrating a large zone of bacterial inhibition.
- No significant reduction in bacterial adhesion was observed, and no correlation existed between inhibition zones and adhesion assay results.
Conclusions:
- Bacterial slime production is a critical factor in Staphylococcus epidermidis adherence to bone cement.
- While gentamicin/clindamycin bone cement exhibited in vitro inhibitory effects, its clinical efficacy in preventing biomaterial-associated infections needs in vivo validation.
