A compound isolated from Alpinia officinarum Hance. inhibits swarming motility of Pseudomonas aeruginosa and down regulates virulence genes

Abstract

Aim:The study was aimed at purifying the active principle from Alpinia officinarum rhizomes responsible for inhibition of swarming motility of Pseudomonas aeruginosa and analysing the mechanism of action. Methods and Results: The active compound from methanol extract of A. officinarum was purified by silica gel column chromatography followed by elution from Amberlite resin. The compound 1-(3,5-dihydroxyphenyl)-2-(methylamino)ethan-1-one, inhibited swarming motility at 12Á5 µg ml À1 . This inhibition was independent of rhamnolipid production. Real-time PCR analysis showed significant down-regulation of virulence-associated genes including T3SS exoS, exoT and flagella master regulator fleQ. Conclusions: The compound from A. officinarum inhibited swarming motility and significantly down-regulated the expression of type III secretory system effector genes exoS and exoT and flagellar master regulator fleQ genes. Significance and Impact of the Study: The study identifies a potent swarming inhibitory compound from the common medicinal plant A. officinarum and reinstates the potential of plant-derived compounds in tackling virulence properties of pathogenic bacteria. et al. 2007) and type III secretory system (T3SS) (Overhage et al. 2008) among others. In addition, swarming cells are also reported to show increased tolerance to antibiotics (Overhage et al. 2008; Lai et al. 2009). Swarming motility was found to be positively associated with clinical features of ocular keratitis (Oka et al. 2015). Although many genes have been identified that regulate swarming motility, it is a complex behaviour involving a network of several genes and pathways including quorum

Antibacterial Activity and Components of the Methanol-Phase Extract from Rhizomes of Pharmacophagous Plant Alpinia officinarum Hance

“…Previous studies have also reported antibacterial activity of the rhizomes of A. officinarum Hance [5,[8][9][10][11]. For example, Lee and Rhee reported that the methanol and ethylacetate combination extracts from fresh rhizomes of A. officinarum Hance were especially effective against four vancomycin-resistant Enterococci strains: E. faecalis (K-10-22), E. faecaium (K-11-212), E. faecalis (K-10-57) and E. faecalis (K-10-361), with MIC values of 12.5, 12.5, 6.25 and 25 µg/mL, respectively.…”

“…This inhibition was independent of rhamnolipid production. Real-time PCR analysis showed significant downregulation of virulence-associated genes, including T3SS exoS, exoT and the flagella master regulator fleQ [10].…”

The Impact of an Efflux Pump Inhibitor on the Activity of Free and Liposomal Antibiotics against Pseudomonas aeruginosa

“…In P. aeruginosa, twitching is modulated by type IV pili and is evident on solid surfaces [79], while swarming is a coordinated group movement on semi-solid surfaces that requires both flagella and type IV pili, and as such, it is regulated by QS [80]. Swimming, on the other hand, occurs in a liquid environment and also requires the use of flagella [79,81]. All those motilities play a determining role in bacterial attachment, colonization and their ability to cause widespread infections [7].…”

Quantitative proteomic reveals gallium maltolate induces an iron-limited stress response and reduced quorum-sensing in Pseudomonas aeruginosa

“…The invasive nature and success of P. aeruginosa in colonising diverse environments is accounted for by twitching/ swarming motilities [105,106], that are modulated by QS pathways with the aid of flagellar movement, to sense and move towards favourable environments [107,108]. A number of regulatory genes are required in flagellar biosynthesis including the anti-sigma-28 factor protein (encoded by flgM) that regulates expression of the B-type flagellin (encoded by fliC) [109], and flgG-encoded flagellar basal-body rod protein FlgG which mediates flagellar rod assembly [110,111].…”