EVALUATION OF DISLODGING METHODS FOR LABORATORY-GROWN BACTERIAL BIOFILMS

The efficacy of Pseudomonas fluorescens and Bacillus subtilis biofilm removal from stainless steel and polyurethane test surfaces by vortexi ng, sonication or shaking with beads, was compared by plate counts and scanning electron microscopy. No significant differences (P>0.01 were found between the bacterial counts resulting from the three methods. However, scanning electron microscopy suggested that shaking with bead s removed cells as well as residues of extracellular polymeric substan ces (EPS) more efficiently from both surface types for both bacteria. Therefore, it was concluded that, based on cell counts and microscopy, shaking with beads was the most suitable method to remove attached P. fluorescens and B. subtilis from stainless steel and polyurethane tes t surfaces. (C) 1997 Academic Press Limited.