SORPTION OF STREPTOCOCCUS FAECIUM TO GLASS

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Abstract
A method was developed to study the sorption of S. faecium to soda-lime cover glasses. Conditions were chosen to minimize the influence on sorption of bacterial polymer production, passive sorption being studied rather than attachment mediated by metabolic activities. Sorption of S. faecium increased with increasing temperature (to 50.degree. C), time and cell concentration, but equilibrium apparently was not reached even after incubation for 8 h or at a cell concentration of 3 .times. 1010/ml. Sorption increased with solute molarity up to 0.1 M concentration of NaCl and KCl, indicating an electrostatic effect of the double layers on the apposition of cells to the glass surface. Desorption of bacteria could be obtained after multiple washings of the glasses in buffer or by the action of Tween 80, but not if sorbed bacteria were left in distilled water, various salt solutions, urea or in suspensions of unlabeled bacteria. Apparently, sorption occurred due to chemical interactions between the glass and the cell surface. Tween 80 at a concentration of 1% inhibited sorption to 26% of buffer controls, 2 M urea was less effective, and 1 M NaCl was without effect. Hydrophobic interactions may be of importance in the binding of S. faecium to glass. [These findings have relevance to the colonization of human teeth by oral streptococci.].