To visualize the biofilm phenotypes, bacteria were grown on LB without salt agar plates containing the dye Congo red (Sigma-Aldrich, Darmstadt, Germany) (40 µg/mL) and Coomassie brilliant blue G-250 (Sigma-Aldrich, Darmstadt, Germany) (20 µg/mL) incubated at 28 and 37 °C. Cell aggregation and pellicle formation were assessed visually after 24 and 48 h, respectively, with cells grown in LB without salt medium in standing culture at 28 and 37 °C. Swimming motility was performed at 37 °C in 0.3% LB agar with the swimming diameter measured after 6 h. Swarming motility was observed in 0.5% Eiken agar with 8% nutrient broth at 37 °C with the swarming diameter measured after 16 h. Control experiments were included as previously described [25 (link),26 (link)].
To visualize E. ludwigii CEB04 biofilm formation on the catheter surface, a part of the catheter was incubated in human urine placed in a 96 well plate and incubated at 37 °C for 24 h. The catheter was washed with PBS and 1% glutardialdehyde was added for 24 h. The catheter was washed again with PBS pH 7.0, dehydrated in an acetone series and critically point-dried. After gold sputter coating, samples were analyzed with a scanning electron microscope (SEM; (Zeiss, Gemini 982, Oberkochen, Germany)) at 5 kV acceleration voltage at 9 mm width.
To visualize E. ludwigii CEB04 biofilm formation on the catheter surface, a part of the catheter was incubated in human urine placed in a 96 well plate and incubated at 37 °C for 24 h. The catheter was washed with PBS and 1% glutardialdehyde was added for 24 h. The catheter was washed again with PBS pH 7.0, dehydrated in an acetone series and critically point-dried. After gold sputter coating, samples were analyzed with a scanning electron microscope (SEM; (Zeiss, Gemini 982, Oberkochen, Germany)) at 5 kV acceleration voltage at 9 mm width.