Effects of quorum sensing molecules of Pseudomonas aeruginosa on organism growth, elastase B production, and primary adhesion to hydrogel contact lenses.
OBJECTIVE
Extracellular proteinase production and biofilm structure of Pseudomonas aeruginosa are affected by acylated homoserine lactones (AHLs) termed quorum sensing (QS) factors. C12- and C4-AHLs of P. aeruginosa and a synthetic furanone signaling antagonist were evaluated for effects on growth, primary adhesion to hydrogel contact lenses, and elastase B production of P. aeruginosa strains, including QS mutants, and isolates of Staphylococcus aureus and Staphylococcus epidermidis.


METHODS
Acylated homoserine lactones and furanone were added to cultures of bacteria at various growth stages. Primary adhesion of P. aeruginosa to lenses soaked in AHLs and furanone was examined by adenosine triphosphate analysis. Elastase B activity of cultures exposed to AHLs and furanone was determined by an elastin congo red assay.


RESULTS
Acylated homoserine lactones had no significant effects on maximal cell densities or primary adhesion. Adhesion of a lasI-rhlI- QS mutant to lenses was significantly lower than its wild-type (WT) strain, regardless of added AHL or furanone. Exogenous AHLs had negligible effects on elastase production of WT P. aeruginosa but restored elastase production in QS-deficient mutants. The furanone was biocidal for staphylococci but enhanced growth of the lasI-rhlI- QS mutant. The furanone decreased elastase production of WT strains but increased QS mutant elastase production.


CONCLUSIONS
Exogenous AHLs and the furanone were of minor importance in initial adhesion of P. aeruginosa to lenses. The furanone decreased staphylococci growth and elastase production of WT P. aeruginosa but increased growth and elastase production of QS mutants. The data further indicate strain diversity in P. aeruginosa and complexity of AHL systems.
George
Melanie
M
Department of Biology, Georgia State University, Atlanta, GA, USA. melanie.george@cibavision.novartis.com
Pierce
George
G
Gabriel
Manal
M
Morris
Carol
C
Ahearn
Donald
D
D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000502:physiology*; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000502:physiology*; D003263:Contact Lenses, Hydrophilic / Q000382:microbiology*; D008666:Metalloendopeptidases / Q000096:biosynthesis*; D011550:Pseudomonas aeruginosa / Q000201:enzymology / Q000254:growth & development*; D013211:Staphylococcus aureus / Q000201:enzymology / Q000254:growth & development; D013212:Staphylococcus epidermidis / Q000201:enzymology / Q000254:growth & development
D001426:Bacterial Proteins; C088386:homoserine lactone; D008666:Metalloendopeptidases; C043859:pseudolysin, Pseudomonas aeruginosa; D015107:4-Butyrolactone