Detection of intracellular bacterial communities and biofilms in urinary tract infections with Escherichia coli using staining protocols

Figure 1 The morphological cycle of intracellular bacterial communities[8] (Supplementary material). IBC: Intracellular bacterial community; UPEC: Uropathogenic Escherichia coli.

Figure 2  Sternheimer-Malbin staining shows bacteria as purple rod-shaped bacilli present within the urothelial cells (arrow).

Figure 3 Wright-Giemsa stain. A: Dense dark-blue bacterial cluster; B: Filamentous bacterial forms (indicated by arrows), highlighting elongated morphology suggestive of intracellular persistence.

Figure 4  Safranin staining showing pink granules of bacterial colonies (arrow) observed within exfoliated urothelial cells.

Figure 5 Immunofluorescence microscopy showing intracellular Escherichia coli within urothelial cells. A: Red fluorescence indicating urothelial cell staining; B: Green fluorescence representing Escherichia coli-specific antibody labeling of bacterial aggregates; C: Merged image showing intracellular co-localization of red and green signals (orange), confirming intracellular bacterial communities.

Figure 6 Scoring of intracellular bacterial communities within uroplakin cells by the four staining methods. IBC: Intracellular bacterial community.

Figure 7  Test tube method showing biofilm formation from strong to weak.