Biofilm production, adherence and morphological alterations of Shigella spp. under salt conditions

Abstract

In this study, we investigated the survival, adhesion and the morphology of Shigella after its incubation in various concentrations of salts. Our results showed that, after 48 h of incubation, the rate of cell survival is inversely proportional to the increase of salinity of the medium. In addition to that, the results prove the evidence that the concentration of salt can significantly influence the capacity of Shigella to produce biofilm on Congo red agar and on polystyrene microplate wells. Adherence and invasion assays of Shigella were performed with KB cells line. Indeed, an increase of the salts concentration enhances the ability of Shigella species to attach and to invade the tissue culture cells. The percentage of adherence was increased to 15% and the invasion to 90% at 6% of salt. The atomic force micrographs showed a reduction of the cells' size after stress. © 2011 Springer-Verlag and the University of Milan.