Print E-mail
Volume 39, Number 4, August 2006

Contribution of quorum-sensing systems to virulence of Pseudomonas aeruginosa in an experimental pyelonephritis model

Rahul Mittal, Saroj Sharma, Sanjay Chhibber, Kusum Harjai
Department of Microbiology, Panjab University, Chandigarh, India

Received: November 11, 2005    Revised: December 1, 2005    Accepted: December 26, 2005   


Corresponding author:

Dr. Kusum Harjai, Department of Microbiology, Biomedical Sciences Block, Panjab University , Chandigarh 160 014, India . E-mail: This e-mail address is being protected from spam bots, you need JavaScript enabled to view it ; This e-mail address is being protected from spam bots, you need JavaScript enabled to view it



Background and purpose: 

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.




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.




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.




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.



Key words:

Animal disease model, Pseudomonas aeruginosa , quorum sensing, virulence



J Microbiol Immunol Infect 2006;39:302-309.