Biofilm formation on glass coverslips. A- Micrographs showing the upper-facing side of the glass coverslips. Biofilms formed by EACF 205 or by EAEC strains were compared with mixed biofilms produced by cocultures of EACF 205 and EAEC strains. EAEC genotype denotes the specific combination of EAEC markers hosted by E. coli strains. Enhanced biofilms were formed by the coculture of EACF 205 and traA-positive EAEC strains. B- Micrographs showing the down-facing side of the glass coverslips. Enhanced biofilms formed by the coculture of EACF 205 and traA-positive EAEC strains indicating an active processes rather than a mere fate following the bacterial settling. C- Quantitative assays. a, b, c, d and e denote P < 0.001 for comparison of 2 groups; f P < 0.05. Statistical analyses: independent-sample T test.