Clove Bud Oil Modulates Pathogenicity Phenotypes of the Opportunistic Human Pathogen Pseudomonas aeruginosa

Sci Rep. 2018 Feb 21;8(1):3437. doi: 10.1038/s41598-018-19771-7.

Abstract

Earlier studies from our laboratory have demonstrated that clove bud oil (CBO) attenuates expression of certain virulence factors of Pseudomonas aeruginosa PAO1. Here, we probe more deeply into the effect of CBO on four pseudomonal proteases - elastase A, elastase B, protease IV and alkaline protease - each known to play key roles in disease pathogenesis. CBO inhibited the activity of these proteases present in the bacterial culture supernatant. Zymography studies indicated that these proteases can activate host matrix metalloproteases (MMPs) to establish infection, through conversion of pro-MMP-2 to active MMP-2. PAO1 is a predominant pathogen in burn wound infections and we show the modulatory effect of CBO on MMPs in an in vitro model of burn injury. Furthermore, CBO induced dose-dependent neutrophil extracellular trap formation in human neutrophils. CBO also increased the survival of C. elegans infected with PAO1, establishing an anti-infective role in a whole animal model of pathogenesis. LC-MS/MS analysis indicated that CBO treatment elicited a significant reduction of signalling molecules (Acyl-Homoserine-Lactone) involved in quorum sensing regulation. Our observations demonstrate that CBO attenuates key virulence mechanisms of this important human pathogen, while concomitantly enhancing host innate immunomodulatory functions, with potential implications for topical therapy against antibiotic-resistant infections.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3-L1 Cells
  • Animals
  • Anti-Bacterial Agents / pharmacology*
  • Anti-Bacterial Agents / therapeutic use
  • Bacterial Proteins / metabolism
  • Caenorhabditis elegans
  • Clove Oil / pharmacology*
  • Clove Oil / therapeutic use
  • Endopeptidases / metabolism
  • Enzyme Inhibitors / pharmacology
  • Extracellular Traps / drug effects
  • Humans
  • Matrix Metalloproteinase 2 / metabolism
  • Mice
  • Pancreatic Elastase / metabolism
  • Peptide Hydrolases / metabolism
  • Pseudomonas Infections / drug therapy*
  • Pseudomonas Infections / metabolism
  • Pseudomonas Infections / microbiology
  • Pseudomonas aeruginosa / drug effects*
  • Pseudomonas aeruginosa / physiology
  • Quorum Sensing / drug effects
  • Virulence / drug effects
  • Virulence Factors / metabolism

Substances

  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Clove Oil
  • Enzyme Inhibitors
  • Virulence Factors
  • Endopeptidases
  • Peptide Hydrolases
  • Pancreatic Elastase
  • Matrix Metalloproteinase 2
  • alkaline protease
  • protease IV