Aqueous extract of cranberry powder downregulates expression of the E. coli gene fliC, which encodes a flagellar protein necessary for movement

Abstract:

Urinary tract infections (UTIs) are the second-most common bacterial infection worldwide and pathogenic Escherichia coli are the major causative agents of such infections.  It is widely thought that cranberry (Vaccinium macrocarpon) can help protect against UTIs.  Research has shown that the mechanism by which cranberries may act is not bacteriostatic, but rather cranberry-containing proanthocyanidins (PACs) reduce movement by affecting flagella production.  The PACs are thought to directly reduce expression of the gene fliC, which encodes a flagellar protein called flagellin that is necessary for movement in the bacterium Escherichia coli.  These researchers used a fliC-lux reporter to assess fliC expression.  Here we develop RT-qPCR methodology to test aqueous cranberry extract and other PAC-containing plant materials.  Primers were designed and tested for fliC and a reference gene, gapA, in a non-pathogenic E. coli (K12).  Sequencing of amplicons was performed to verify RT-qPCR products.  Expression of fliC was compared for E. coli K12 grown in different concentrations of aqueous cranberry extract:  0 mg/ml, 5 mg/ml, 10 mg/ml, and 20 mg/ml.  In each case fliC expression was lower than the control.