Effects of hutZEp mutation on biofilm growth. A Biofilm-forming capacity of E. piscicida. TX01 and TX01ΔhutZ were incubated in polystyrene plates, and biofilm formation was determined by measuring the A570 of the final eluates. B The viability of biofilm growth of E. piscicida as determined by confocal laser scanning microscopy (CLSM). Cells in the biofilms were stained with a BacLight LIVE/DEAD kit to reveal viable (green fluorescence) and non-viable (red fluorescence) bacteria. Data are presented as the means ± SEMs (N = 3). N, the number of times the experiment was performed. **P < 0.01.