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A Study of Surface Motility and Biofilm Formation in Pseudomonas aeruginosa: Quorum Sensing and Photodynamic Antimicrobial Chemotherapy

Collins, Tracy Lynn
http://rave.ohiolink.edu/etdc/view?acc_num=dayton1291235249

Abstract Details

2010, Doctor of Philosophy (Ph.D.), University of Dayton, Biology.
Pseudomonas aeruginosa is an opportunistic pathogen that commonly causes infection in immunocompromised individuals. This bacterium forms complex communities known as biofilms. Biofilm formation is dependent on motility as well as quorum-sensing. In this study, we show that P. aeruginosa surface motility is inhibited in the presence of the quorum-sensing molecule E,E-farnesol. In the presence of E,E-farnesol, there is an 4-fold increase in rhamnolipid production. Because swarming motility is dependent on rhamnolipid production, this increase could account for the inhibition in swarming motility observed in the presence of E,E-farnesol. In addition, the effect of the cationic porphyrin 5,10,15,20-tetrakis(1-methyl-pyridino)-21H,23H-porphine, tetra-p-tosylate salt (TMP) on P. aeruginosa biofilms was examined. Exposure to 225 µM TMP and photoactivation resulted in almost complete killing of biofilm associated cell as well as the detachment of wild-type PAO1 biofilms. In contrast, pqsA mutant biofilms that contain less extracellular DNA remained intact. Our results suggest that the action of photoactivated TMP on P. aeruginosa biofilms is two-fold: direct killing of individual cells within biofilms and detachment of the biofilm from the substratum. There was no evidence of porphyrin toxicity in the absence of light; however, biofilms pretreated with TMP without photoactivation were substantially more sensitive to tobramycin than untreated biofilms.
Jayne Robinson, PhD (Advisor)
Mark Nielsen, PhD (Committee Member)
Carissa Krane, PhD (Committee Member)
John Rowe, PhD (Committee Member)
Shawn Swavey, PhD (Committee Member)
136 p.
Biology; Microbiology; Molecular Biology
Pseudomonas aeruginosa; biofilms; photodynamic therapy; porphyrin; swarming motility; twitching motility; farnesol; rhamnolipids; quorum sensing

Recommended Citations

Citations

  • Collins, T. L. (2010). A Study of Surface Motility and Biofilm Formation in Pseudomonas aeruginosa: Quorum Sensing and Photodynamic Antimicrobial Chemotherapy [Doctoral dissertation, University of Dayton]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1291235249

    APA Style (7th edition)

  • Collins, Tracy. A Study of Surface Motility and Biofilm Formation in Pseudomonas aeruginosa: Quorum Sensing and Photodynamic Antimicrobial Chemotherapy. 2010. University of Dayton, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=dayton1291235249.

    MLA Style (8th edition)

  • Collins, Tracy. "A Study of Surface Motility and Biofilm Formation in Pseudomonas aeruginosa: Quorum Sensing and Photodynamic Antimicrobial Chemotherapy." Doctoral dissertation, University of Dayton, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1291235249

    Chicago Manual of Style (17th edition)

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This open access ETD is published by University of Dayton and OhioLINK.