Fig. 4

Effect of gallic acid-ceftiofur combination on the viability of cultured biofilm. The confocal laser scanning microscope images of BacLight LIVE/DEAD stained biofilms of Salmonella enterica serovar Typhimurium (ATCC14028) treated with (A) no drug, (B) gallic acid (½ × MIC), (C) ceftiofur (½ × MIC), and (D) gallic acid (½ × MIC) + ceftiofur (½ × MIC). The viability of the biofilm cells was assessed using BacLight LIVE/DEAD stain (green: live cells, red: dead cells). Four different segments are present in each of the images (A, B, C and D) where, the top left segment shows only SYTO9-stained cells, the top right segment displays only propidium iodide-stained cells, and below left and below right segments show merged images of both SYTO9-stained cells and propidium iodide-stained cells from an individual sample. In each image, the segment at below right side shows three dimensional and other three segments show two dimensional images