1887

Abstract

The virulence of in contact lens-induced microbial keratitis has been linked to various extracellular and cell-associated bacterial products, such as proteases and toxins. Recently, a group of bacterial signal molecules, -acyl-homoserine lactones (AHLs), has been reported to play an important role in the regulation of the production of several bacterial virulence factors in. The aim of this study was to determine the signal molecules produced by keratitis strains, and to elucidate any possible correlation between the production of signal molecules and the expression of phenotypic characteristics, including protease production, bacterial invasion and acute cytotoxic activity. The presence and profiles of AHLs in ocular isolates were analysed by a combination of thin-layer chromatography and bioassay. All 17 keratitis isolates produced AHLs. There were differences both in the amounts and the types of AHL production in the various phenotypes of isolates. High levels of AHLs were found among the isolates with high protease activity and invasiveness. Acutely cytotoxic isolates displayed low AHL and protease activities. Invasive strains were more common than cytotoxic strains from keratitis patients. These results suggest that quorum-sensing systems of display a complexity even within the same species, and the production of certain AHL signal molecules may be associated with certain phenotypes in .

Loading

Article metrics loading...

/content/journal/jmm/10.1099/0022-1317-51-12-1063
2002-12-01
2024-11-05
Loading full text...

Full text loading...

/deliver/fulltext/jmm/51/12/1063.html?itemId=/content/journal/jmm/10.1099/0022-1317-51-12-1063&mimeType=html&fmt=ahah

References

  1. Cheng KH, Leung SL, Hoekman HW. et al. Incidence of contact-lens-associated microbial keratitis and its related morbidity. Lancet 1999; 354:181–185 [CrossRef]
    [Google Scholar]
  2. Donshik PC. Contact lenses and microbial keratitis. CLAO J 1997; 23:148
    [Google Scholar]
  3. Twining SS, Kirschner SE, Mahnke LA, Frank DW. Effect of Pseudomonas aeruginosa elastase, alkaline protease, and exotoxin A on corneal proteinases and proteins. Invest Ophthalmol Vis Sci 1993; 34:2699–2712
    [Google Scholar]
  4. O'Callaghan RJ, Engel LS, Hobden JA, Callegan MC, Green LC, Hill JM. Pseudomonas keratitis.The role of an uncharacterized exoprotein, protease IV, in corneal virulence. Invest Ophthalmol Vis Sci 1996; 37:534–543
    [Google Scholar]
  5. Iglewski BH, Burns RP, Gipson IK. Pathogenesis of corneal damage from Pseudomonas exotoxin A. Invest Ophthalmol Vis Sci 1977; 16:73–76
    [Google Scholar]
  6. Krall R, Sun J, Pederson KJ, Barbieri JT. In vivo Rho GTPase-activating protein activity of Pseudomonas aeruginosa cytotoxin ExoS. Infect Immun 2002; 70:360–367 [CrossRef]
    [Google Scholar]
  7. Fuqua C, Winans SC, Greenberg EP. Census and consensus in bacterial ecosystems: the LuxR-LuxI family of quorum-sensing transcriptional regulators. Annu Rev Microbiol 1996; 50:727–751 [CrossRef]
    [Google Scholar]
  8. Passador L, Cook JM, Gambello MJ, Rust L, Iglewski BH. Expression of Pseudomonas aeruginosa virulence genes requires cell-to-cell communication. Science 1993; 260:1127–1130 [CrossRef]
    [Google Scholar]
  9. Gambello MJ, Iglewski BH. Cloning and characterization of the Pseudomonas aeruginosa lasR gene, a transcriptional activator of elastase expression. J Bacteriol 1991; 173:3000–3009
    [Google Scholar]
  10. Toder DS, Gambello MJ, Iglewski BH. Pseudomonas aeruginosa LasA: a second elastase under the transcriptional control of lasR. Mol Microbiol 1991; 5:2003–2010 [CrossRef]
    [Google Scholar]
  11. Gambello MJ, Kaye S, Iglewski BH. LasR of Pseudomonas aeruginosa is a transcriptional activator of the alkaline protease gene ( apr ) and an enhancer of exotoxin A expression. Infect Immun 1993; 61:1180–1184
    [Google Scholar]
  12. Davies DG, Parsek MR, Pearson JP, Iglewski BH, Costerton JW, Greenberg EP. The involvement of cell-to-cell signals in the development of a bacterial biofilm. Science 1998; 280:295–298 [CrossRef]
    [Google Scholar]
  13. Pearson JP, Passador L, Iglewski BH, Greenberg EP. A second N -acylhomoserine lactone signal produced by Pseudomonas aeruginosa . Proc Natl Acad Sci USA 1995; 92:1490–1494 [CrossRef]
    [Google Scholar]
  14. Pearson JP, Van Delden C, Iglewski BH. Active efflux and diffusion are involved in transport of Pseudomonas aeruginosa cell-to-cell signals. J Bacteriol 1999; 181:1203–1210
    [Google Scholar]
  15. Brint JM, Ohman DE. Synthesis of multiple exoproducts in Pseudomonas aeruginosa is under the control of RhlR-RhlI, another set of regulators in strain PAO1 with homology to the autoinducer-responsive LuxR-LuxI family. J Bacteriol 1995; 177:7155–7163
    [Google Scholar]
  16. Latifi A, Winson MK, Foglino M. et al. Multiple homologues of LuxR and LuxI control expression of virulence determinants and secondary metabolites through quorum sensing in Pseudomonas aeruginosa PAO1. Mol Microbiol 1995; 17:333–343 [CrossRef]
    [Google Scholar]
  17. Pesci EC, Milbank JBJ, Pearson JP. et al. Quinolone signaling in the cell-to-cell communication system of Pseudomonas aeruginosa . Proc Natl Acad Sci USA 1999; 96:11229–11234 [CrossRef]
    [Google Scholar]
  18. Morihara K, Homma JY. Pseudomonas proteases In Holder JA. ed Bacterial enzymes and virulence Boca Raton, FL: CRC Press; 1985
    [Google Scholar]
  19. Engel LS, Hobden JA, Moreau JM, Callegan MC, Hill JM, O'Callaghan RJ. Pseudomonas deficient in protease IV has significantly reduced corneal virulence. Invest Ophthalmol Vis Sci 1997; 38:1535–1542
    [Google Scholar]
  20. Engel LS, Hill JM, Moreau JM, Green LC, Hobden JA, O'Callaghan RJ. Pseudomonas aeruginosa protease IV produces corneal damage and contributes to bacterial virulence. Invest Ophthalmol Vis Sci 1998; 39:662–665
    [Google Scholar]
  21. Engel LS, Hill JM, Caballero AR, Green LC, O'Callaghan RJ. Protease IV, a unique extracellular protease and virulence factor from Pseudomonas aeruginosa . J Biol Chem 1998; 273:16792–16797 [CrossRef]
    [Google Scholar]
  22. Fleiszig SM, Lee EJ, Wu C. et al. Cytotoxic strains of Pseudomonas aeruginosa can damage the intact corneal surface in vitro . CLAO J 1998; 24:41–47
    [Google Scholar]
  23. Cole N, Willcox MD, Fleiszig SM. et al. Different strains of Pseudomonas aeruginosa isolated from ocular infections or inflammation display distinct corneal pathologies in an animal model. Curr Eye Res 1998; 17:730–735 [CrossRef]
    [Google Scholar]
  24. Cowell BA, Willcox MD, Hobden JA, Schneider RP, Tout S, Hazlett LD. An ocular strain of Pseudomonas aeruginosa is inflammatory but not virulent in the scarified mouse model. Exp Eye Res 1998; 67:347–356 [CrossRef]
    [Google Scholar]
  25. Cole N, Bao S, Thakur A, Willcox M, Husband AJ. KC production in the cornea in response to Pseudomonas aeruginosa challenge. Immunol Cell Biol 2000; 78:1–4 [CrossRef]
    [Google Scholar]
  26. Fleiszig SM, Wiener-Kronish JP, Miyazaki H. et al. Pseudomonas aeruginosa -mediated cytotoxicity and invasion correlate with distinct genotypes at the loci encoding exoenzyme S. Infect Immun 1997; 65:579–586
    [Google Scholar]
  27. Zhu H, Thuruthyil SJ, Willcox MDP. Production of N -acyl homoserine lactones by Gram-negative bacteria isolated from contact lens wearers. Clin Exp Ophthalmol 2001; 29:150–152 [CrossRef]
    [Google Scholar]
  28. Miller J. ed Experiments in molecular genetics Cold Spring Harbor, NY, Cold Spring Harbor Laboratory Press; 1976
    [Google Scholar]
  29. Fuqua C, Winans S. Conserved cis -acting promoter elements are required for density-dependent transcription of Agrobacterium tumefaciens conjugal transfer genes. J Bacteriol 1996; 178:435–440
    [Google Scholar]
  30. Shaw PD, Ping G, Daly SL. et al. Detecting and characterizing N -acyl-homoserine lactone signal molecules by thin-layer chromatography. Proc Natl Acad Sci USA 1997; 94:6036–6041 [CrossRef]
    [Google Scholar]
  31. McClean KH, Winson MK, Fish L. et al. Quorum sensing and Chromobacterium violaceum : exploitation of violacein production and inhibition for the detection of N -acylhomoserine lactones. Microbiology 1997; 143:3703–3711 [CrossRef]
    [Google Scholar]
  32. Zhu H, Thuruthyil SJ, Willcox MDP. Invasive strains of Pseudomonas aeruginosa are able to cause epithelial cell cytotoxicity that is dependent on bacterial cell density. Clin Exp Ophthalmol 2000; 28:201–204 [CrossRef]
    [Google Scholar]
  33. Howe TR, Iglewski BH. Isolation and characterization of alkaline protease-deficient mutants of Pseudomonas aeruginosa in vitro and in a mouse eye model. Infect Immun 1984; 43:1058–1063
    [Google Scholar]
  34. Schad PA, Bever RA, Nicas TI, Leduc F, Hanne LF, Iglewski BH. Cloning and characterization of elastase genes from Pseudomonas aeruginosa . J Bacteriol 1987; 169:2691–2696
    [Google Scholar]
  35. Heussen C, Dowdle ED. Electrophoretic analysis of plasminogen activators in polyacrylamide gels containing sodium dodecyl sulfate and copolymerized substrates. Anal Biochem 1980; 102:196–202 [CrossRef]
    [Google Scholar]
  36. Araki-Sasaki K, Ohashi Y, Sasabe T. et al. An SV40-immortalized human corneal epithelial cell line and its characterization. Invest Ophthalmol Vis Sci 1995; 36:614–621
    [Google Scholar]
  37. Jumblatt MM, Neufeld AH. Beta-adrenergic and serotonergic responsiveness of rabbit corneal epithelial cells in culture. Invest Ophthalmol Vis Sci 1983; 24:1139–1143
    [Google Scholar]
  38. Fleiszig SM, Zaidi TS, Fletcher EL, Preston MJ, Pier GB. Pseudomonas aeruginosa invades corneal epithelial cells during experimental infection. Infect Immun 1994; 62:3485–3493
    [Google Scholar]
  39. Fleiszig SM, Zaidi TS, Preston MJ, Grout M, Evans DJ, Pier GB. Relationship between cytotoxicity and corneal epithelial cell invasion by clinical isolates of Pseudomonas aeruginosa . Infect Immun 1996; 64:2288–2294
    [Google Scholar]
  40. Pearson JP, Gray KM, Passador L. et al. Structure of the autoinducer required for expression of Pseudomonas aeruginosa virulence genes. Proc Natl Acad Sci USA 1994; 91:197–201 [CrossRef]
    [Google Scholar]
  41. Winson MK, Camara M, Latifi A. et al. Multiple N -acyl-l-homoserine lactone signal molecules regulate production of virulence determinants and secondary metabolites in Pseudomonas aeruginosa . Proc Natl Acad Sci USA 1995; 92:9427–9431 [CrossRef]
    [Google Scholar]
  42. Geisenberger O, Givskov M, Riedel K, Hoiby N, Tummler B, Eberl L. Production of N -acyl-l-homoserine lactones by Pseudomonas aeruginosa isolates from chronic lung infections associated with cystic fibrosis. FEMS Microbiol Lett 2000; 184:273–278
    [Google Scholar]
  43. Singh PK, Schaefer AL, Parsek MR, Moninger TO, Welsh MJ, Greenberg EP. Quorum-sensing signals indicate that cystic fibrosis lungs are infected with bacterial biofilms. Nature 2000; 407:762–764 [CrossRef]
    [Google Scholar]
  44. Finck-Barbancon V, Goranson J, Zhu L. et al. ExoU expression by Pseudomonas aeruginosa correlates with acute cytotoxicity and epithelial injury. Mol Microbiol 1997; 25:547–57 [CrossRef]
    [Google Scholar]
  45. Wilson R, Sykes DA, Watson D, Rutman A, Taylor GW, Cole PJ. Measurement of Pseudomonas aeruginosa phenazine pigments in sputum and assessment of their contribution to sputum sol toxicity for respiratory epithelium. Infect Immun 1988; 56:2515–2517
    [Google Scholar]
/content/journal/jmm/10.1099/0022-1317-51-12-1063
Loading
/content/journal/jmm/10.1099/0022-1317-51-12-1063
Loading

Data & Media loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error