The contribution of quorum sensing in some phenotypic and pathogenic characteristics of Pseudomonas aeruginosa was studied. The production of acylhomoserine lactones (AHL) by planktonic cultures of eight clinical and reference strains of P. aeruginosa was evaluated using two biosensors. The adhesion of the bacteria on a surface (Biofilm Ring Test ®, BFRT), their capacity to develop a biofilm (crystal violet staining method, CVSM), their sensitivity to tobramycin and their secretion of proteases or of rhamnolipids were also measured. The production and the release of AHL widely varied among the eight strains. An analysis of the extracts by TLC showed that 3-oxo-C8-HSL, 3-oxo-C10-HSL and 3-oxo-C12-HSL were released by the five strains producing the highest amount of C≥6-HSL. The genes lasI and lasR involved in the synthesis and response to 3-oxo-C12-HSL were detected in the genomes of all strains. Two clinical strains had deletions in the lasR gene leading to truncation of the protein. One subpopulation of the PAO1 strain had a major deletion (98 bp) of the lasR gene. Strains with significant mutations of lasR secreted the lowest amount of AHL, probably due to deficiencies in the self-induction and amplification of the synthesis of the lactone. These strains formed a biofilm with low biomass. C4-HSL production also differed among the strains and was correlated with rhamnolipid production and biofilm formation. Whereas the production of AHL varied among P. aeruginosa strains, few correlations were observed with their phenotypic properties except with their ability to form a biofilm.
BottomleyM. J., MuragliaE., BazzoR., CarfìA.2007; Molecular insights into quorum sensing in the human pathogen Pseudomonas aeruginosa from the structure of the virulence regulator LasR bound to its autoinducer. J Biol Chem 282:13592–13600 [View Article][PubMed]
EricksonD. L., EndersbyR., KirkhamA., StuberK., VollmanD. D., RabinH. R., MitchellI., StoreyD. G.2002; Pseudomonas aeruginosa quorum-sensing systems may control virulence factor expression in the lungs of patients with cystic fibrosis. Infect Immun 70:1783–1790 [View Article][PubMed]
EssarD. W., EberlyL., HaderoA., CrawfordI. P.1990; Identification and characterization of genes for a second anthranilate synthase in Pseudomonas aeruginosa: interchangeability of the two anthranilate synthases and evolutionary implications. J Bacteriol 172:884–900[PubMed]
FridkinS. K., StewardC. D., EdwardsJ. R., PryorE. R., McGowanJ. E.Jr, ArchibaldL. K., GaynesR. P., TenoverF. C.1999; Surveillance of antimicrobial use and antimicrobial resistance in United States hospitals: project ICARE phase 2. Project Intensive Care Antimicrobial Resistance Epidemiology (ICARE) hospitals. Clin Infect Dis 29:245–252 [View Article][PubMed]
FuquaW. C., WinansS. C., GreenbergE. P.1994; Quorum sensing in bacteria: the LuxR-LuxI family of cell density-responsive transcriptional regulators. J Bacteriol 176:269–275[PubMed]
GeisenbergerO., GivskovM., RiedelK., HøibyN., TümmlerB., EberlL.2000; Production of N-acyl-l-homoserine lactones by P. aeruginosa isolates from chronic lung infections associated with cystic fibrosis. FEMS Microbiol Lett 184:273–278[PubMed]
MoskowitzS. M., FosterJ. M., EmersonJ., BurnsJ. L.2004; Clinically feasible biofilm susceptibility assay for isolates of Pseudomonas aeruginosa from patients with cystic fibrosis. J Clin Microbiol 42:1915–1922 [View Article][PubMed]
NagantC., Tré-HardyM., DevleeschouwerM., DehayeJ. P.2010a; Study of the initial phase of biofilm formation using a biofomic approach. J Microbiol Methods 82:243–248 [View Article][PubMed]
NagantC., Tré-HardyM., El-OuaalitiM., SavageP., DevleeschouwerM., DehayeJ. P.2010b; Interaction between tobramycin and CSA-13 on clinical isolates of Pseudomonas aeruginosa in a model of young and mature biofilms. Appl Microbiol Biotechnol 88:251–263 [View Article][PubMed]
OchsnerU. A., ReiserJ.1995; Autoinducer-mediated regulation of rhamnolipid biosurfactant synthesis in Pseudomonas aeruginosa. Proc Natl Acad Sci U S A 92:6424–6428 [View Article][PubMed]
ParsekM. R., GreenbergE. P.2005; Sociomicrobiology: the connections between quorum sensing and biofilms. Trends Microbiol 13:27–33 [View Article][PubMed]
SandozK. M., MitzimbergS. M., SchusterM.2007; Social cheating in Pseudomonas aeruginosa quorum sensing. Proc Natl Acad Sci U S A 104:15876–15881 [View Article][PubMed]
SchaberJ. A., CartyN. L., McDonaldN. A., GrahamE. D., CheluvappaR., GriswoldJ. A., HamoodA. N.2004; Analysis of quorum sensing-deficient clinical isolates of Pseudomonas aeruginosa.. J Med Microbiol 53:841–853 [View Article][PubMed]
ShawP. D., PingG., DalyS. L., ChaC., CronanJ. E.Jr, RinehartK. L., FarrandS. K.1997; Detecting and characterizing N-acyl-homoserine lactone signal molecules by thin-layer chromatography. Proc Natl Acad Sci U S A 94:6036–6041 [View Article][PubMed]
SmithE. E., BuckleyD. G., WuZ., SaenphimmachakC., HoffmanL. R., D’ArgenioD. A., MillerS. I., RamseyB. W., SpeertD. P. et al.2006; Genetic adaptation by Pseudomonas aeruginosa to the airways of cystic fibrosis patients. Proc Natl Acad Sci U S A 103:8487–8492 [View Article][PubMed]
VandeputteO. M., KiendrebeogoM., RasamiravakaT., StévignyC., DuezP., RajaonsonS., DialloB., MolA., BaucherM., El JaziriM.2011; The flavanone naringenin reduces the production of quorum sensing-controlled virulence factors in Pseudomonas aeruginosa PAO1. Microbiology 157:2120–2132 [View Article][PubMed]
WilhelmS., GdyniaA., TielenP., RosenauF., JaegerK. E.2007; The autotransporter esterase EstA of Pseudomonas aeruginosa is required for rhamnolipid production, cell motility, and biofilm formation. J Bacteriol 189:6695–6703 [View Article][PubMed]