Burdock root extracts limit quorum-sensing-controlled phenotypes and biofilm architecture in major urinary tract pathogens

Satish Kumar Rajasekharan, Samiraj Ramesh, Dhamodharan Bakkiyaraj, Ramaraj Elangomathavan, Chakkaravarthi Kamalanathan

Bacterial biofilms are serious concern in patients infected with urinary tract infections, complicated urinary tract infections and other device-associated infections. Microbes within the biofilms are effectively shielded from antibiotics and host immune cells, hence can be treated only with agents which has the potential to disassemble the biofilms. The study is focused on the root extracts of Arctium lappa Linn. as a source for complementary medicine against three major biofilm forming clinical isolates of Escherichia coli, Proteus mirabilis, and Serratia marcescens. Methanol extracts of burdock roots (BR) showed no bactericidal activity (p > 0.05) against the uropathogens, whereas restrained the biofilms (p < 0.05) on polystyrene and glass surfaces at a biofilm inhibitory concentration of 100 µg/mL. The 3D confocal laser scanning microscopy was used to analyze the biofilm architecture which showed significant reduction in the surface area. Z-stack analysis has also revealed substantial reduction in the biofilm thickness (E. coli-50.79 %, P. mirabilis-69.49 %, and S. marcescens-75.84 %). Further, BR extracts also inhibited quorum-sensing (QS)-controlled cellular phenotypes such as violacein, prodigiosin, swarming motility, and cell surface hydrophobicity. LC-MS/MS analysis of BR extracts identified the presence of two major quercetin derivatives (miquelianin and peltatoside) along with few other constituent components. Exploring such phytocompounds will provide potential agents to treat infections caused by biofilm forming uropathogens. The antibiofilm and anti-QS agents will ultimately serve as armor, facilitating the host immune system to fight infections.