Cranberry derived proanthocyanidins induce a state of iron-limitation in uropathogenic Escherichia coli CFT073 as revealed by microarray analysis

Transcriptional profiles of uropathogenic Escherichia coli CFT073 exposed to cranberry-derived proanthocyanidins (PACs) were determined. Our results indicate that bacteria grown on media supplemented with PACs were iron-deprived. To our knowledge, this is the first time that PACs have been shown to induce a state of iron-limitation in this bacterium. Cultures of E. coli CFT073 were streaked onto LB agar plates and incubated (37°C, 24 h). A single colony was inoculated into 150 mL of LB broth. Three inoculated flasks contained LB broth alone (controls), and three inoculated flasks were supplemented with cranberry PACs (100 µg/mL). After incubation (37°C, 5 h, 200 rpm to mid-log growth phase), bacteria were harvested for RNA extraction.