Graduation Term

Spring 2025

Degree Name

Master of Science (MS)

Department

School of Biological Sciences

Committee Chair

Jan-Ulrik Dahl

Committee Member

Brian Wilkinson

Committee Member

Kyle Floyd

Abstract

The rise in drug-resistant bacteria, together with the decline in antibiotic development, requires new strategies for infectious disease control. Gram-negative pathogens are particularly challenging to combat due to their outer membrane. This study highlights the effectiveness of the silver-containing antimicrobial AGXX® against the Gram-negative bacterium Escherichia coli. AGXX® is a promising silver coating that presumably kills bacteria through the generation of reactive oxygen species (ROS). However, neither AGXX®’s mode of action is fully understood, nor have its effects on Gram-negative bacteria or bacterial response and defense mechanisms towards AGXX® been studied in detail. Here, I report that the bactericidal effects of AGXX® are primarily based on ROS formation, as supplementation of the media with a ROS scavenger completely abolished AGXX®-induced killing. Further, AGXX® effectively reduces bacterial survival by interfering with membrane integrity and causing DNA damage and protein aggregation, which is likely a consequence of uncontrolled generation of oxidative stress. Finally, I present evidence that the production of the chaperone polyphosphate protects cells from AGXX-mediated protein aggregation. Our findings emphasize AGXX®’s potential as an antimicrobial surface coating and shed light on potential targets to reduce bacterial resistance to AGXX®.

Access Type

Thesis-Open Access

DOI

https://doi.org/10.30707/ETD.1763755358.714088

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