Identification and Inhibition of Fosfomycin Resistance Enzymes for Structure-Based Drug Design

Antimicrobial resistance (AMR) is a pressing issue facing modern medicine today. Bacteria are developing resistance to antibiotics faster than new antibiotics can be brought to market. Antimicrobial resistant infections are responsible for increased morbidity and mortality rates, as well as an economic burden with increased duration of care and costs of treatments. The development of new antibiotics to combat bacterial resistance is a long and costly process and has resulted in pharmaceutical companies turning away from the traditional drug development pipeline. One alternative method to address AMR is through repurposing existing approved drugs such as by utilizing combination drug therapies. Combination drug therapies often involve the inhibition of antibiotic modifying enzymes found within bacteria. This research aims to use combination therapy to restore the functionality of the drug fosfomycin by using in silico high-throughput virtual screening (HTVS) to identify inhibitors of fosfomycin resistance enzymes.The purpose of this work is to characterize fosfomycin resistance enzymes and identify enzymatic inhibitors to restore the functionality of fosfomycin. First, we identified and characterized the fosfomycin resistance enzyme in Enterococcus faecium (FosBEf). Our goal was to structurally characterize the bacillithiol binding site, however we discovered FosBEf is unique among the FosB enzyme family and utilizes L-cys as the preferred thiol substrate and produced limited enzymatic activity with BSH. Next, we focused on identifying and characterizing inhibitors of the fosfomycin resistance protein in Pseudomonas aeruginosa (FosAPa). Initially we compared the structural and kinetic properties of established inhibitors of other classes of fosfoymcin resistance enzymes on FosA. Then we utilized in silico high-throughput virtual screening (HTVS) to identify halogenated inhibitors to modify the absorption, distribution, metabolism, and excretion properties and potential permeability into P. aeruginosa. Taken together, the findings of this work provide a scaffold for future structure-based drug design for restoring fosfomycin activity.

Grantor dc:publisher

University of Alabama Libraries

Year dc:date.issued

2025

Author dc:creator

• Wiltsie, Vanessa

Advisor dc:contributor.advisor

• Thompson, Matthew K.

Contributors dc:contributor

• Frantom, Patrick A.
• Pierce, Brad S.
• Szulczewski, Gregory J.
• Ciesla, Lukasz M.

• Antimicrobial Resistance
• Crystallography
• Fosfomycin
• Glutathione

Statement dc:rights

• All rights reserved by the author unless otherwise indicated.

Language dc:language.iso

en_US, English

Dc Identifier Other

1177362

OAI identifier oai:identifier

oai:ir.ua.edu:123456789/17076