[In vivo and in vitro analysis of the ability of urinary catheter to microbial colonization].

Bacterial adhesion to biomaterials is a complex phenomenon involving numerous factors. The ability to reduce urinary catheters infections simply by general hygiene and asepsis is low: an ascending colonization cannot be avoided. This will lead to a clinical infection only if several factors favour the bacterial adhesion or the bacterial coaggregation and the feeding of the bacterial biofilm. Among the many factors involved in bacterial adhesion, we focused in this paper on the physical parameters of surface hydrophobicity of the urinary catheters (Van der Waals and acido-basic forces) and the surface hydrophobicity of the bacteria (BATH and zeta potential). We also compared scanning electron microscopy (SEM) of in vivo and in vitro infected urinary catheters. We provided evidence that the more hydrophobic the bacteria, the more they are able to colonize hydrophobic materials, whereas hydrophilic cells are able to colonize hydrophilic materials more easily. Some biomaterials were found to display an irregular texture of hydrophobic and hydrophilic areas: they favour both types of adhesion. Moreover the divalent cations (MgII) drastically increased the bacterial coaggregation and favour bacterial growth within the biofilm. Finally, an increase in urinary pH and ionic strength increases the colonization risk. Consequently, choice of urinary catheter biomaterials is essential as patient hygiene and diet in order to avoid clinical infections.