Firstly, the biofilm formation of A

Firstly, the biofilm formation of AbIC IΔblp1 and AbIC IIΔblp1 mutants and their blp1-complemented strains was assessed. Bacteria were grown on the plastic surface and the formed structures were analyzed by confocal laser scanning microscopy (CLSM) using SYTO9 and propidium iodide (PI) staining as described in Materials and Methods. Interestingly, 2 h post-seeding, the initial attachment of bacteria to the plastic surface, based on the increase of PI-stained (red stain) versus total amount of bacteria (green stain) was affected in AbIC IΔblp1 mutant, demonstrating up to 55% increase in PI-stained bacteria compared with the parental strain (Fig. 2a, upper panels).