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Nitric oxide tolerance and antimicrobial susceptibility in Escherichia coli clinical isolates

A. Ribeiro, Cláudia (2018) Nitric oxide tolerance and antimicrobial susceptibility in Escherichia coli clinical isolates. Doctor of Philosophy (PhD) thesis, University of Kent,. (KAR id:73097)

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The emergence of antibiotic resistance has been a serious concern for the last few decades. It hinders the treatment of infectious diseases, raising mortality and morbidity rates, as well as increasing the cost of healthcare. To investigate the problem of antibiotic resistant E. coli, 50 E. coli bacteraemia clinical isolates (Kent collection) were collected from East Kent Hospitals University NHS Foundation and phenotypically/genotypically characterized for antibiotic resistance, virulence factors, and the presence of putative plasmids. High levels of resistance were detected for amoxicillin and trimethoprim, and 14% of the isolates showed a multidrug-resistant phenotype. ST73 isolates exhibited the highest virulence potential while ST131 exhibited the highest levels of antibiotic resistance, although no correlation was detected between the two variables. In accordance with previous observations, co-carriage of CTX-M-15 and aac(3)-IIa, aac(6')Ib-cr, and blaOXA was observed in the collection, providing a possible explanation on why ESBL-producing isolates are often multidrug resistant.

The work herein reports that NO elicits a dramatic increase in the tolerance of E. coli to antibiotics. Hence, this work has revealed a huge void in knowledge related to

antibiotic potency during conditions relevant to infection (i.e. in the presence of NO). Furthermore, this work reveals that the cytochrome bd-I respiratory oxidase sensitises E. coli to antibiotics in the presence of NO. These findings shed light on how NO encountered during infection could impair the function of antibiotics and will prompt future research into how controlling levels of respiratory inhibition during infection may be used to improve antibiotic efficacy.

Item Type: Thesis (Doctor of Philosophy (PhD))
Thesis advisor: Shepherd, Mark
Divisions: Divisions > Division of Natural Sciences > School of Biosciences
SWORD Depositor: System Moodle
Depositing User: System Moodle
Date Deposited: 05 Apr 2019 07:39 UTC
Last Modified: 20 May 2021 13:26 UTC
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