Inhibition of biofilm formation and swarming of Escherichia coli by (5Z)‐4‐bromo‐5‐(bromomethylene)‐3‐butyl‐2(5H)‐furanone

Abstract

The quorum-sensing disrupter (5Z)-4-bromo-5-(bromomethylene)-3-butyl-2(5H)-furanone (furanone) of the alga Delisea pulchra was found to inhibit the swarming motility of Escherichia coli completely at 13 microg cm-2 (also at 20 microg ml-1) but did not inhibit its growth rate at 13-52 microg cm-2 or from 20 to 100 microg ml-1. Swimming was not inhibited by the furanone at 20-40 microg ml-1. In addition, confocal scanning laser microscopy revealed that this furanone at 60 microg ml-1 inhibited the biofilm formation of E. coli, as it decreased its thickness by 55%, reduced the number of water channels and decreased the percentage of live cells by 87%. This suggests that natural furanone may be used as a new method to control bacterial biofilms that does not involve toxicity. Furanone at 10 microg ml-1 also inhibited by 3300-fold the quorum sensing of Vibrio harveyi via autoinducer 1 (AI-1) and inhibited by 5500-fold that of V. harveyi via of autoinducer 2 (AI-2) as well as inhibited by 26-600-fold the quorum sensing of E. coli via AI-2; hence, this furanone is a non-specific intercellular signal antagonist.

Quorum Sensing in Plaque Biofilms: Challenges and Future Prospects

“…AI-2 promotes biofilm and swimming motility in E. coli. 32 Ren et al 33,34 found that swarming activity and biofilm formation by E. coli, were inhibited by (5Z)-4-bromo-5-(bromomethylene)-3-butyl-2-(5H)-furanone at levels that had no effect on bacterial growth; however, swimming was not inhibited. The brominated furanone decreased the concentration of AI-2 but had no effect on luxS and pfs genes, which encode the proteins for AI-2 production.…”

Role of biofilm in catheter-associated urinary tract infection☆

“…84 Also, addition of furanone, a quorum-sensing disrupter, to cultures of E coli markedly decreased biofilm thickness. 85 These studies suggest that manipulating evolutionarily conserved cell-to-cell signaling methods may be a means to prevent or limit biofilm formation by uropathogens. Unfortunately, the clinical use of furanones is limited by potential toxicity and by variable efficacy in different studies.…”

Quorum quenching quandary: resistance to antivirulence compounds

“…The natural compound (5Z)-4-bromo-5-(bromomethylene)-3-butyl-2(5H)-furanone from D. pulchra inhibits both acyl-homoserine lactone-based and autoinducer 2-based QS (Ren et al, 2001), and the synthetic furanone C-30 ( Figure 1a inset) has been shown to decrease acylhomoserine lactone-based signaling as well as decrease the virulence of P. aeruginosa in a mouse pulmonary infection model (Hentzer et al, 2003). These brominated furanones interrupt QS by interacting with transcriptional regulators that propagate the QS response (Defoirdt et al, 2007), and they do not affect bacterial growth in rich medium (Gram et al, 1996;Ren et al, 2001;Hentzer et al, 2003). However, growth of pathogens in the host during infections is more likely to involve non-robust carbon sources and may involve compounds whose utilization depends on QS (Defoirdt et al, 2010).…”