title: Inhibition of Escherichia coli CFT073 fliC expression and motility by cranberry materials.
abstract: In humans, uropathogenic Escherichia coli (UPEC) is the most common etiological agent of uncomplicated urinary tract infections (UTIs). Cranberry extracts have been linked to the prevention of UTIs for over a century; however, a mechanistic understanding of the way in which cranberry derivatives prevent bacterial infection is still lacking. In this study, we used a fliC-lux reporter as well as quantitative reverse transcription-PCR to demonstrate that when UPEC strain CFT073 was grown or exposed to dehydrated, crushed cranberries or to purified cranberry-derived proanthocyanidins (cPACs), expression of the flagellin gene (fliC) was inhibited. In agreement with these results, transmission electron microscopy imaging of bacteria grown in the presence of cranberry materials revealed fewer flagella than those in bacteria grown under control conditions. Furthermore, we showed that swimming and swarming motilities were hindered when bacteria were grown in the presence of the cranberry compounds. Because flagellum-mediated motility has been suggested to enable UPEC to disseminate to the upper urinary tract, we propose that inhibition of flagellum-mediated motility might be a key mechanism by which cPACs prevent UTIs. This is the first report to show that cranberry compounds inhibit UPEC motility via downregulation of the fliC gene. Further studies are required to establish whether these inhibitors play a role in vivo.
authors.affiliation: Department of Chemical Engineering, McGill University, 3610 University Street, Montreal, Quebec H3A 2B2, Canada.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Hidalgo
authors.forename: Michelle
authors.initials: M
authors.lastname: Chan
authors.forename: Nathalie
authors.initials: N
authors.lastname: Tufenkji
mesh_terms: D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D019677:Artificial Gene Fusion; D029968:Escherichia coli Proteins / Q000096:biosynthesis*; D005407:Flagella / Q000187:drug effects / Q000502:physiology; D005408:Flagellin; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D017930:Genes, Reporter; D008124:Locomotion / Q000187:drug effects*; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D056689:Uropathogenic Escherichia coli / Q000187:drug effects* / Q000502:physiology; D029799:Vaccinium macrocarpon / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D029968:Escherichia coli Proteins; C516095:FliC protein, E coli; D010936:Plant Extracts; D005408:Flagellin; D008156:Luciferases