FIG. 3.

Ultrastructure of K. pneumoniae biofilms. K. pneumoniae strain RYC492 was incubated for 24 hr on abiotic surfaces (A–J) or on immobilized human lung cells (K–M). Bacteria were stained with an anti-K. pneumoniae antibody followed by an Alexa 555 conjugated secondary antibody and bacterial DNA was stained with TOPRO3, which was pseudocolored in green (A–J) or blue (L, M) for better visualization. Confocal microscopy XY images showing optical sections (A) top, (B) middle, and (C) bottom. XY projections of (D) capsule stain, (E) DNA stain, or (F) merged images. (G–J) Optical sections of YZ images collected across the biofilm structure. XY projection of (K) capsule stain, (L) DNA stain, or (M) merged images.