Item Details

title

Eradication of Staphylococcus aureus Biofilm on Photothermal Silicone Nanocomposites

author

Vargas, Erica Monette Medina

abstract

Many health care-associated infections (HCAIs) stem from biofilm growth on indwelling silicone medical devices. Current treatments involve antibiotics or device removal. However, these treatments are not the most effective for antibiotic resistant biofilms. We propose to use photothermal therapy (PTT) to eradicate biofilms on medical devices. PTT was applied on two well characterized strains of Staphylococcus aureus biofilms, Xen29 and Xen40, with a laser using various powers (W) and times (s). Xen29 is from the parental strain, American Type Culture Collection (ATCC) 12600, and Xen40 is a clinical isolate derived from UAMS-1. The overall goal was to demonstrate the effectiveness of PTT materials against S. aureus biofilms and discover its mechanisms on individual biofilm structures following treatment. Results showed significant reductions in colony forming units (CFU) and biomass for both strains. Xen29 was further evaluated with a kinetic assay and the results showed a decreasing trend in CFU/mL over a 24-hour incubation period using 5W,60s. Additionally, fluorescent microscopy images illustrated the damaging effects of PTT on live cells, polysaccharides, and extracellular DNA. Based on the findings presented in this study, PTT was an effective form of treatment in significantly reducing (>3-log10 reduction) the number of viable bacteria in CFU/mL and degrading individual biofilm structures that contribute to biofilm maturation.

subject

Biofilms

Extracellular DNA

Infection

Nanoparticles

Polysaccharides

Silicone

contributor

Zafar, Muhammad A (advisor)

Levi, Nicole H (committee member)

Palavecino, Elizabeth L (committee member)

date

2024-05-23T08:36:26Z (accessioned)

2025-05-22T08:30:08Z (available)

2024 (issued)

degree

Biomedical Science – MS (discipline)

embargo

2025-05-22 (terms)

identifier

http://hdl.handle.net/10339/109456 (uri)

language

en (iso)

publisher

Wake Forest University

type

Thesis