Quorum sensing


Quorum sensing is the capacity of micro-organisms to detect extracellular, small-molecule signals and to alter gene expression in response to microbial population densities

  • These molecules are used by bacteria to modulate gene expression within their own species, as well as competing bacteria and even eukaryotes
  • Successful invasion of a host is a collective process, based on microbial information sharing and active collaboration
  • Quorum sensing inhibitors have potential roles as therapeutic agents


Many bacterial pathogen contain QS genes that may help coordinate host invasion (e.g. expression of virulence genes), such as:

  • Streptococcus spp
  • Staphylococcus spp
  • Escherichia coli
  • Pseudomonas aeruginosa
  • Bacteroides spp
  • Yersinia spp
  • Burkholderia spp
  • Enterococcus spp


  • Autoinducer type 1, LuxR-I type
  • Autoinducer type 2, LuxS type
  • Autoinducer type 3, epinephrine/norepinephrine signaling system
  • Cyclic short-peptide systems


  • biofilm production and maintenance
  • regulation of the bacterial virulome (virulence genes)
  • disruption of the quorum sensing systems of competing species
  • inhibition of growth of competing species
  • modulation of host response to bacterial invasion
  • sensing host stress response

References and Links

Journal articles

  • Asad S, Opal SM. Bench-to-bedside review: Quorum sensing and the role of cell-to-cell communication during invasive bacterial infection. Crit Care. 2008;12(6):236. doi: 10.1186/cc7101.PMC2646340.

CCC 700 6

Critical Care


Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of three amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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