Date of Award
8-2025
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Microbiology
Committee Chair/Advisor
Xuiping Jiang
Committee Member
Harry Kurtz Jr.
Committee Member
Kristi Whitehead
Committee Member
David Buckley
Abstract
Biofilms are resistant to many stressors including disinfectant treatments. Disinfection may be further complicated by biofilms formed on damaged surfaces, as the damaged parts provide bacteria a better place to attach and grow. To better understand the risks, a new method to standardize surface scratching, to emulate worn surfaces via surface roughness changes was developed. These surfaces were used to grow biofilms with an adapted standardized EPA method to determine disinfection efficacy differences on scratched and non-scratched high-density polyethylene (HDPE) and stainless steel (SS) coupons treated with commercial disinfectants [hypochlorite (CL)-based, hydrogen peroxide (HP)-based, and quaternary ammonium (QA)-based]. Post-80 grit sandpaper scratching, average surface roughness of SS and HDPE increased by 0.82 µm and 12.69 µm, respectively. Early-phase biofilms were more pronounced on 80 grit-scratched surfaces versus smooth surfaces; no significant difference for mature biofilms was detected. Disinfection treatments achieved biofilm log reductions/coupon ranging from 3.23 to 6.22 (Pseudomonas aeruginosa) and 2.92 to 5.62 (Staphylococcus aureus). Biocide comparisons revealed HP and CL disinfectants performed significantly better than QA on HDPE. CL and QA performed significantly better than HP on SS against P. aeruginosa. The desired 6 log/coupon reduction was only achieved against P. aeruginosa grown on a non-scratched HDPE coupon treated with CL. Overall, bacteria, surface material, roughness, and disinfectants affected the biofilm disinfection.
Recommended Citation
Stallings, Kayley, "Determining the Impact of Surface Roughness on Disinfection Efficacy of Commercial Products Against Pseudomonas aeruginosa and Staphylococcus aureus Wet Surface Biofilms" (2025). All Theses. 4586.
https://open.clemson.edu/all_theses/4586
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