2.5. Desiccation assay

To evaluate the effect of capsule production and biofilm formation on bacterial tolerance to desiccation, MCE membranes with planktonic cells or colony biofilms were placed in a desiccator for 0, 1, 3, 7, 28 days respectively. At each time point, planktonic/biofilm-containing MCE membranes were removed from the desiccator and placed into a 15 mL FALCON tube containing 5 mL phosphate-buffered saline (PBS), followed by vortex using a multi-vortex mixer at maximum speed for 2 min and sonication for 10 min in a sonication bath (frequency = 42 kHz). The number of survivor cells was determined by colony-forming unit (CFU) enumeration. This assay was performed in three biological repeats in technical duplicate.