Using a Proteomics-based Approach to Uncover Mechanisms of Antibiotic Resistance in Epidemic Strains of Pseudomonas aeruginosa

Date

Authors

Goodyear, Mara

Journal Title

Journal ISSN

Volume Title

Publisher

University of Guelph

Abstract

Pseudomonas aeruginosa is a Gram-negative bacterium that can cause chronic and multidrug-resistant infections. Understanding and predicting the antibiotic resistance profiles of clinical isolates of P. aeruginosa is important for developing and administering effective treatments against this opportunistic pathogen. Label-free quantitative proteomics can be used to identify the abundances of proteins produced by clinical isolates of P. aeruginosa under different conditions. The proteomics data can then be used to complement genomic, transcriptomic, and phenotypic data to help predict antibiotic resistance profiles, and to identify the molecular mechanisms of antibiotic resistance in clinical isolates of P. aeruginosa. In this thesis research, I completed phenotypic and proteomic characterization of isolates of the Liverpool Epidemic Strain (LES) of P. aeruginosa. I first provide a comprehensive analysis of the growth and antibiotic susceptibility of eight LES isolates grown as both planktonic and biofilm cultures. Two isolates, LESlike1 and LESB58, with different antibiotic resistance profiles were chosen for proteomic characterization and comparison with the laboratory strain PAO1. In my comparison of the proteomes of LESlike1, LESB58, and PAO1 I demonstrate the potential for proteomic data to predict antibiotic resistance phenotypes that could not be determined from genomic data alone. I next compared the proteomes of LESlike1, LESB58, and PAO1 after they were challenged with one of five treatments (four antibiotics and hydrogen peroxide) to identify their adaptive responses to antibiotic treatment. This analysis identified proteins with different abundances between the three isolates and challenge conditions that can be further characterized to understand their contributions to antibiotic resistance. Specifically, I identified differential abundances of proteins involved in cell wall synthesis and division in LESB58 in response to the antibiotic carbenicillin. The inner membrane protein CreD was increased in abundance with high-fold changes in LESB58 and an additional beta-lactam resistant isolate exposed to carbenicillin, and I report the results of the initial characterization of knockout strains of creD. Overall, this work describes a proteomic dataset that will facilitate further study of protein-based resistance in clinically important isolates of P. aeruginosa.

Description

Keywords

Pseudomonas aeruginosa, antibiotic resistance, proteomics, Liverpool Epidemic Strain

Citation

Goodyear MC, Garnier NE, Levesque RC, Khursigara C. 2022. Liverpool Epidemic Strain isolates of Pseudomonas aeruginosa display high levels of antimicrobial resistance during both planktonic and biofilm growth June:e01024-22. https://doi.org/10.1128/spectrum.01024-22.
Goodyear MC, Garnier N, Krieger JR, Geddes-McAlister J, Khursigara CM. 2021. Label-free quantitative proteomics identifies unique proteomes of clinical isolates of the Liverpool Epidemic Strain of Pseudomonas aeruginosa and laboratory strain PAO1. Proteomics Clin Appl 15:e2100062. https://doi.org/10.1002/prca.202100062