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Inhibition of Microbial Quorum Sensing Mediated Virulence Factors by Pestalotiopsis sydowiana

Paramanantham Parasuraman1, B Devadatha2, V Venkateswara Sarma2

  • 1Department of Microbiology, School of Life Sciences, Pondicherry University, Puducherry 605014, India.

Journal of Microbiology and Biotechnology
|January 28, 2020
PubMed

Insights

Marine fungus extract effectively inhibits Pseudomonas aeruginosa virulence by disrupting quorum sensing (QS). This study identifies potent compounds that reduce bacterial infection factors, offering a novel strategy against antibiotic-resistant pathogens.

Area of Science:

  • Marine microbiology and natural product chemistry
  • Antimicrobial drug discovery and development
  • Bacterial pathogenesis and virulence factor inhibition

Background:

  • Quorum sensing (QS) mediated infections pose significant health risks, necessitating alternative strategies to combat antibiotic-resistant bacteria.
  • Marine fungi represent a rich source of bioactive compounds with potential antipathogenic properties.
  • Pseudomonas aeruginosa infections are a major concern due to their virulence and resistance to conventional antibiotics.

Purpose of the Study:

  • To evaluate the antipathogenic potential of the marine fungus Pestalotiopsis sydowiana PPR extract against Pseudomonas aeruginosa.
  • To investigate the effect of fungal extract and its metabolites on QS-regulated virulence factors and biofilm formation.
  • To identify and characterize the specific bioactive compounds responsible for the observed antivirulence activity.

Main Methods:

  • Determination of the minimum inhibitory concentration (MIC) of fungal extract and identified compounds against P. aeruginosa PAO1.
  • Assessment of sub-MIC effects on QS-controlled virulence factors (pyocyanin, protease, elastase, etc.) and exopolysaccharide production.
  • In silico analysis of metabolite-receptor interactions and identification of potent compounds (Cyclo(-Leu-Pro) and 4-Hydroxyphenylacetamide) using computational approaches.

Main Results:

  • Sub-MIC concentrations of P. sydowiana PPR extract significantly reduced pyocyanin, chitinase, protease, elastase, and staphylolytic activity.
  • The extract also inhibited exopolysaccharide, rhamnolipid, and alginate production, leading to a substantial reduction in biofilm formation (90.54%).
  • In silico analysis identified Cyclo(-Leu-Pro) and 4-Hydroxyphenylacetamide as key metabolites binding to QS receptors (LasR and RhlR), with significant antivirulence effects observed at sub-MIC levels.

Conclusions:

  • Metabolites from Pestalotiopsis sydowiana PPR exhibit potent quorum sensing inhibitory activity against Pseudomonas aeruginosa.
  • These findings highlight the potential of marine fungal-derived compounds as novel antipathogenic agents to combat bacterial infections.
  • The identified compounds, Cyclo(-Leu-Pro) and 4-Hydroxyphenylacetamide, represent promising candidates for developing new anti-virulence therapies.
Keywords:
Pestalotiopsis sydowianaPseudomonas aeruginosaanti-biofilmanti-quorum sensinggene expressionin silico

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