Fig 8. The effect of FeCl₃ on the inhibition of Af biofilm formation, by filtrate from a CF non-mucoid Pa grown under biofilm conditions.

Conidia formed biofilms on polystyrene disks (AF) during 16 h exposure to Pa filtrate (PA), filtrate + varying concentrations of FeCl₃ (shown as the concentration, uM = μM), or varying concentrations of FeCl₃ only. After 16 h of challenge, disks were transferred to fresh RPMI-1640 for 24 h of further growth before biofilm formation was quantified via XTT assay, and the results expressed as percent of control with medium alone (no supernatant or FeCl₃). Asterisks denote P <0.001 for comparisons to the experimental control containing Af with RPMI-1640 (AF; no test materials). Daggers denote P <0.001 for comparisons with the experimental control containing Af +filtrate (AF + PA). Results with AF + PA + 11, 33 or 99 μM FeCl₃ were not different than AF + PA; AF + 11, 33, or 99 μM FeCl₃ were not different than AF + 297 μM FeCl₃; and these results are not shown.