The standard treatment for uncomplicated UTIs is empiric therapy with antibiotics (Hummers-Pradier & Kochen, 2000); however, the rising clinical failure rates caused by uropathogen resistance to antibiotics (Gupta, 2002; Prais et al., 2003; Foxman, 2010) has heightened the interest in the development of alternative therapies for the prevention and treatment of UTIs. A wide range of natural products have been screened for their

nutraceutical characteristics, including pomegranate (Punica granatum) (Macnab, 1992; Lansky & Newman, 2007). For example, it has been shown that pomegranate rind extract (PGRE), in combination with a range of metal salts, exhibited antimicrobial activity against Staphylococcus aureus CDK assay (Braga et al., 2005; Gould et al., 2009), E. coli, Pseudomonas aeruginosa (Duman et al., 2009), and Proteus mirabilis (McCarrell et al., 2008). We previously showed that the swimming and swarming motility of UPEC were hindered in the presence of cranberry compounds and that

this motility inhibition resulted from a decrease in the expression of fliC (Hidalgo et al., 2011). The overall aim of this study was to explore the effect of pomegranate materials (PMs) on UPEC. Three types of PMs were tested: PGRE, pomegranate tannins (PG), and pomegranate fruit powder (PGP). Specifically, we investigated whether exposure to PMs would result in the downregulation of the fliC gene of E. coli Selleck BI 6727 CFT073 and the corresponding drop in flagellin protein production and whether this would result in impaired bacterial motility. Because flagellar motility

has been suggested to enable UPEC to disseminate to the upper urinary tract (Lane et al., 2007a, b) and considering the current rising rates of antibiotic resistance, research on the effects of PMs on the gene regulation and phenotype of this ubiquitous uropathogenic bacterium is of great relevance. Escherichia coli strain CFT073 (ATCC 700928) (wild-type pyelonephritis isolate, laboratory collection) and CFT073 PfliC-lux (Lane et al., 2007a, b) (flagellin-transcription reporter vector; SB-3CT ampr) were used as the test bacteria in this study. Escherichia coli CFT073 ΔfliC (CFT073 fliC::aphA; kanr) was used as a negative control. Cultures were grown in LB medium (10 g L−1 tryptone, 10 g L−1 NaCl, and 5 g L−1 yeast extract). Planktonic bacterial cultures were incubated at 37 °C and rotary shaking at 200 r.p.m. unless otherwise indicated. Ampicillin and kanamycin were supplemented as needed at final concentrations of 100 and 50 μg mL−1, respectively. HPLC grade PG (Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island) and PGP (Navitas Naturals) were solubilized in distilled, deionized water to concentrations of 1.5 and 100 mg mL−1, respectively, and sterilized by filtration. PGRE was prepared as described by McCarrell et al. (2008).