Fig. 1

A flowchart of the experimental design describes the steps performed with 24-h biofilm. 46 steel plates with established 24-h biofilm were subjected to epifluorescence microscopy before and after sonication. The number of CFU in the sonication fluid was calculated. Confocal laser scanning microscopy (CLSM) was applied to 4 of the 46 specimen and scanning electron microscopy (SEM) to 2 of the 46 specimen for confirmation of possible presence of coccoid bacteria after sonication. 2 additional positive controls, which were not sonicated, were visualized with SEM to see that the preparation did not affect the biofilm