title: Inhibition of quorum-sensing-controlled virulence factors of Pseudomonas aeruginosa by Murraya koenigii essential oil: a study in a Caenorhabditis elegans infectious model.
abstract: The global emergence of antibiotic-resistant strains of Pseudomonas aeruginosa poses a major threat in both hospital environments and the community. P. aeruginosa is an opportunistic human pathogen, and it also infects a wide range of model organisms including the nematode Caenorhabditis elegans. Quorum sensing (QS) mediates cell-to-cell communication in bacteria and has an important role in regulating virulence genes, antibiotic resistance and biofilm formation, which are crucial for establishment of the infection. Expression of many virulence factors such as pyocyanin and proteases in P. aeruginosa is under the control of the QS system, and are mediated by small molecules such as acyl homoserine lactones. Thus, interfering with the QS system would provide alternative ways of controlling the pathogenicity. Murraya koenigii is a medicinal plant widely used in India. The present study investigated the in vivo inhibitory activity of M. koenigii essential oil (EO) on QS-controlled virulence factors of P. aeruginosa PAO1 using C. elegans. M. koenigii EO significantly inhibited the pyocyanin production and staphylolytic LasA activity of P. aeruginosa PAO1. As compared to the control group with 100 % killing of C. elegans, M. koenigii EO was able to rescue an average of 60 % of C. elegans from death due to the toxic effect of P. aeruginosa. Thus, the present study suggests the anti-QS potential of M. koenigii EO which therefore can be considered as a future therapeutic agent for management of P. aeruginosa-mediated infections.
authors.affiliation: Department of Studies in Microbiology, University of Mysore, Manasagangotri, Mysore 570006, Karnataka, India.
authors.forename: P Sankar
authors.initials: PS
authors.lastname: Ganesh
authors.affiliation: Department of Studies in Microbiology, University of Mysore, Manasagangotri, Mysore 570006, Karnataka, India.
authors.forename: Ravishankar Vittal
authors.initials: RV
authors.lastname: Rai
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D018441:Biofilms / Q000187:drug effects; D017173:Caenorhabditis elegans / Q000382:microbiology*; D004195:Disease Models, Animal; D006801:Humans; D007194:India; D032101:Murraya / Q000737:chemistry*; D009822:Oils, Volatile / Q000494:pharmacology*; D010938:Plant Oils / Q000494:pharmacology*; D011552:Pseudomonas Infections / Q000188:drug therapy / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000187:drug effects*; D053038:Quorum Sensing / Q000187:drug effects*; D037521:Virulence Factors / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D009822:Oils, Volatile; D010938:Plant Oils; D037521:Virulence Factors