Fig. 2.

P. aeruginosa biofilms exposed to ferric ammonium citrate. GFP expressing OPPA8 and PAO1 strains were grown in flow chambers for 48 hours and subsequently exposed to 100 and 250 μmol/L of ferric ammonium citrate for an additional 24 hours. Confocal laser microscopy was utilized to create three-dimensional reconstructions of the PA biofilms. Representative images of the three-dimensional biofilm reconstructions are shown. FAC at 100 and 250 μmol/L significantly decreased the fluorescence of OPPA8 biofilms. Propidium iodine staining of dead bacteria was seen in the OPPA8 cultures after exposure to FAC. In contrast, FAC at 100 and 250 μmol/L did not statistically reduce the bacterial volume of established PAO1 biofilms.