Waar Karola, van der Mei Henny C, Harmsen Hermie J M, Degener John E, Busscher Henk J
Department of Medical Microbiology. Department of Biomedical Engineering, University of Groningen, 9713 GZ Groningen, The Netherlands.
Appl Environ Microbiol. 2002 Aug;68(8):3855-8. doi: 10.1128/AEM.68.8.3855-3858.2002.
The aim of this study is to determine whether growth in the presence of bile influences the surface properties and adhesion to hydrophobic bile drain materials of Enterococcus faecalis strains expressing aggregation substance (Agg) or enterococcal surface protein (Esp), two surface proteins that are associated with infections. After growth in the presence of bile, the strains were generally more hydrophobic by water contact angles and the zeta potentials were more negative than when the strains were grown in the absence of bile. Nitrogen was found in lower surface concentrations upon growth in the presence of bile, whereas higher surface concentrations of oxygen were measured by X-ray photoelectron spectroscopy. Moreover, an up to twofold-higher number of bacteria adhered after growth in bile for E. faecalis not expressing Agg or Esp and E. faecalis with Esp on its surface. E. faecalis expressing Agg did not adhere in higher numbers after growth in bile, possibly because they mainly adhere through positive cooperativity and less through direct interactions with a substratum surface. Since adhesion of bacteria is the first step in biomaterial-centered infection, it can be concluded that growth in bile increases the virulence of E. faecalis.
本研究的目的是确定在胆汁存在下生长是否会影响表达聚集物质（Agg）或肠球菌表面蛋白（Esp）的粪肠球菌菌株的表面特性及其对疏水性胆汁引流材料的粘附性，这两种表面蛋白与感染相关。在胆汁存在下生长后，通过水接触角测量，菌株通常更具疏水性，并且与在无胆汁条件下生长时相比，ζ电位更负。通过X射线光电子能谱法测得，在胆汁存在下生长时，表面氮浓度较低，而氧的表面浓度较高。此外，对于不表达Agg或Esp的粪肠球菌以及表面带有Esp的粪肠球菌，在胆汁中生长后细菌的粘附数量增加了两倍之多。表达Agg的粪肠球菌在胆汁中生长后粘附数量并未增加，这可能是因为它们主要通过正协同作用粘附，而较少通过与基质表面的直接相互作用粘附。由于细菌粘附是生物材料相关感染的第一步，因此可以得出结论，在胆汁中生长会增加粪肠球菌的毒力。
