title: Contribution of quorum-sensing systems to virulence of Pseudomonas aeruginosa in an experimental pyelonephritis model.
abstract: OBJECTIVE
  Pseudomonas aeruginosa has been reported to monitor its cell density as well as expression of virulence determinants by quorum-sensing signal mechanisms operative through autoinducers. In the present investigation, we studied the contribution of quorum-sensing signals during the course of P. aeruginosa-induced pyelonephritis in mice.
  
  
  METHODS
  The standard parent strain of P. aeruginosa (PAO1), possessing functional las and rhl quorum-sensing systems and its isogenic mutant strains, PAO-JP1 (single mutant), harboring a mutated lasI gene and PAO-JP3 (double mutant), harboring mutated lasI and rhlR genes were employed. One uroisolate of P. aeruginosa belonging to serotype O8 and deficient in production of quorum-sensing signals was also used.
  
  
  RESULTS
  The parent strain of P. aeruginosa was significantly more virulent compared to its isogenic mutant strains and quorum-sensing negative clinical strain, as assessed by neutrophil influx, malondialdehyde production, renal bacterial load and pathology induced in experimental animals.
  
  
  CONCLUSIONS
  Quorum-sensing systems play an important role in the pathogenicity of P. aeruginosa in pyelonephritis. Both the las and rhl quorum-sensing systems are important for the virulence of P. aeruginosa in the development of pyelonephritis.
authors.affiliation: Department of Microbiology, Panjab University, Chandigarh, India. rahul_mittal20022@yahoo.com
authors.forename: Rahul
authors.initials: R
authors.lastname: Mittal
authors.forename: Saroj
authors.initials: S
authors.lastname: Sharma
authors.forename: Sanjay
authors.initials: S
authors.lastname: Chhibber
authors.forename: Kusum
authors.initials: K
authors.lastname: Harjai
mesh_terms: D000818:Animals; D005260:Female; D006801:Humans; D051379:Mice; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D011704:Pyelonephritis / Q000382:microbiology* / Q000473:pathology; D053038:Quorum Sensing / Q000502:physiology*; D014774:Virulence