Reproducible biofilm cultivation of chemostat-grown Escherichia coli and investigation of bacterial adhesion on biomaterials using a non-constant-depth film fermenter

PLoS One. 2014 Jan 3;9(1):e84837. doi: 10.1371/journal.pone.0084837. eCollection 2014.

Abstract

Biomaterials-associated infections are primarily initiated by the adhesion of microorganisms on the biomaterial surfaces and subsequent biofilm formation. Understanding the fundamental microbial adhesion mechanisms and biofilm development is crucial for developing strategies to prevent such infections. Suitable in vitro systems for biofilm cultivation and bacterial adhesion at controllable, constant and reproducible conditions are indispensable. This study aimed (i) to modify the previously described constant-depth film fermenter for the reproducible cultivation of biofilms at non-depth-restricted, constant and low shear conditions and (ii) to use this system to elucidate bacterial adhesion kinetics on different biomaterials, focusing on biomaterials surface nanoroughness and hydrophobicity. Chemostat-grown Escherichia coli were used for biofilm cultivation on titanium oxide and investigating bacterial adhesion over time on titanium oxide, poly(styrene), poly(tetrafluoroethylene) and glass. Using chemostat-grown microbial cells (single-species continuous culture) minimized variations between the biofilms cultivated during different experimental runs. Bacterial adhesion on biomaterials comprised an initial lag-phase I followed by a fast adhesion phase II and a phase of saturation III. With increasing biomaterials surface nanoroughness and increasing hydrophobicity, adhesion rates increased during phases I and II. The influence of materials surface hydrophobicity seemed to exceed that of nanoroughness during the lag-phase I, whereas it was vice versa during adhesion phase II. This study introduces the non-constant-depth film fermenter in combination with a chemostat culture to allow for a controlled approach to reproducibly cultivate biofilms and to investigate bacterial adhesion kinetics at constant and low shear conditions. The findings will support developing and adequate testing of biomaterials surface modifications eventually preventing biomaterial-associated infections.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Adhesion*
  • Batch Cell Culture Techniques
  • Biocompatible Materials*
  • Biofilms*
  • Escherichia coli / physiology*
  • Fermentation
  • Hydrophobic and Hydrophilic Interactions
  • Surface Properties
  • Titanium / chemistry

Substances

  • Biocompatible Materials
  • titanium dioxide
  • Titanium

Grant support

This work was supported by the Excellence Graduate School “Jena School for Microbial Communication” (JSMC MikroInter supported by the Thüringer Ministerium für Bildung, Wissenschaft und Kultur TMBWK) which is funded by the German Excellence Initiative. KDJ gratefully acknowledges, furthermore, the partial financial support of the Deutsche Forschungsgemeinschaft (DFG), grant reference INST 275/241-1 FUGG, and of the Thüringer Ministerium für Bildung, Wissenschaft und Kultur (TMBWK), grant reference 62-4264 925/1/10/1/01. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.