title: Interference of quorum sensing in urinary pathogen Serratia marcescens by Anethum graveolens.
abstract: Serratia marcescens is an opportunistic turned obligate pathogen frequently associated with urinary tract infections (UTI) and are multidrug resistant at most instances. Quorum sensing (QS) system, a population-dependent global regulatory system, controls the pathogenesis machinery of S. marcescens as it does in other pathogens. In the present study, methanol extract of a common herb and spice, Anethum graveolens (AGME) was assessed for its anti-QS potential against the clinical isolate of S. marcescens. AGME notably reduced the biofilm formation and QS-dependent virulence factors production in a concentration-dependent manner (64-1024 μg mL(-1)). The light and confocal microscopic images clearly evidenced the antibiofilm activity of AGME (256 μg mL(-1)) at its minimal biofilm inhibitory concentration. Besides, in support of biochemical assays, the expression analysis of QS-regulated genes fimC, bsmA and flhD which are crucial for initial adhesion and motility confirmed their downregulation upon exposure to AGME. LC-MS analysis of AGME revealed 3-O-methyl ellagic acid (3-O-ME) as one of its active principles having nearly similar antibiofilm activity and a reduced inhibition of prodigiosin (27%) and protease (15%) compared to AGME [prodigiosin (47%) and protease (50%)]. UFLC analysis revealed that 0.355 mg g(-1) of 3-O-ME was present in the AGME. AGME and the 3-O-ME significantly interfered the QS system of a QS model strain S. marcescens MG1 and its mutant S. marcescens MG44 which in turn corroborates the anti-QS mechanism of AGME.
authors.affiliation: Department of Biotechnology, Alagappa University, Science Campus, Karaikudi-630004, Tamil Nadu, India.
authors.forename: Ramesh
authors.initials: R
authors.lastname: Salini
authors.affiliation: Department of Biotechnology, Alagappa University, Science Campus, Karaikudi-630004, Tamil Nadu, India sk_pandian@rediffmail.com.
authors.forename: Shunmugiah Karutha
authors.initials: SK
authors.lastname: Pandian
mesh_terms: D028524:Anethum graveolens / Q000737:chemistry*; D001426:Bacterial Proteins / Q000096:biosynthesis; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development; D002853:Chromatography, Liquid; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D006801:Humans; D013058:Mass Spectrometry; D008826:Microbial Sensitivity Tests; D008853:Microscopy; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D053038:Quorum Sensing / Q000187:drug effects*; D016868:Serratia Infections / Q000382:microbiology*; D012706:Serratia marcescens / Q000187:drug effects* / Q000302:isolation & purification / Q000502:physiology*; D014552:Urinary Tract Infections / Q000382:microbiology*
chemical_list: D001426:Bacterial Proteins; D010936:Plant Extracts
keywords: 3-O-methyl ellagic acid; Anethum graveolens; Serratia marcescens; biofilm; quorum sensing