Representative micrographs of mono- and mixed-species biofilms composed Salmonella Agona and selected resident flora strains. Mono-species biofilms were composed of Staphylococcus piscifermentans (A), Pantoea agglomerans (B), Pseudomonas sp. (C), S. Agona (D), and mixed-species biofilms were composed of S. Agona with S. piscifermentans (E), P. agglomerans (F) and Pseudomonas sp. (G). Biofilms were stained using the nucleic acid dye, Syto 61, for observation using laser scanning confocal microscopy. GFP-tagged S. Agona cells were used. Biofilms were grown using TSB as growth medium at 25°C for two days in the Drip Flow Biofilm Reactor. For each micrograph, vertical sections of the biofilms (in the yz-plane) are presented with the left-side of each section corresponding to the substratum. In mixed-species biofilms, green cells represent pGFP-uv-tagged S. Agona, red cells correspond to SYTO 61-stained resident flora bacteria, and yellow cells represent GFP-tagged S. Agona marked with SYTO 61. Scale bars represent 50 μm.