Contribution of quorum-sensing systems to virulence of Pseudomonas aeruginosa in an experimental pyelonephritis model.
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.
Mittal
Rahul
R
Department of Microbiology, Panjab University, Chandigarh, India. rahul_mittal20022@yahoo.com
Sharma
Saroj
S
Chhibber
Sanjay
S
Harjai
Kusum
K
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