Fig. 4
The antibacterial effect of CORM-2 on colonization of host cells and localization of colonized bacteria. Quantification and immunofluorescence staining of ESBL-producing isolate 6 following colonization of 5637 bladder epithelial cells. A gentamycin protection assay was used to support intracellular growth of the bacteria. a Host bladder 5637 cells were lysed and the lysate serially diluted and plated on TSA plates for quantification of bacterial count (CFU/ml). Bacterial counts in cell lysate was evaluated after exposure for 4 h to DMSO, the CO-free molecule Ru(DMSO)4Cl2 (500 μM), cefotaxime (0.512 μg/ml) or CORM-2 (250 and 500 μM). Data are presented as mean ± SEM from four independent experiments. *P < 0.05, CORM-2 versus DMSO. b-d Immunofluorescence staining of ESBL-producing isolate 6 following infection of 5637 bladder epithelial cells. Staining of the bladder cell nuclei was performed with DAPI and is shown in blue. ESBL isolate 6 are stained b) in red (extracellular) prior to permeabilization, and c) in green (extracellular and intracellular) after permeabilization. d Merged image of B and C where several intracellular bacteria are seen as green stain (arrows) and extracellular bacteria are shown as merged red and green (yellow) stain (arrowhead). Scale bar = 10 μm