Envelope proteome changes driven by RamA overproduction in Klebsiella pneumoniae that enhance acquired β-lactam resistance.

Autor:	Jiménez-Castellanos JC; School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK., Wan Nur Ismah WAK; School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK.; Faculty of Biotechnology & Biomolecular Sciences, Universiti Putra Malaysia, Selangor Darul Ehsan, Malaysia., Takebayashi Y; School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK., Findlay J; School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK., Schneiders T; Division of Infection and Pathway Medicine, University of Edinburgh, Edinburgh, UK., Heesom KJ; University of Bristol Proteomics Facility, Bristol, UK., Avison MB; School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK.
Jazyk:	angličtina
Zdroj:	The Journal of antimicrobial chemotherapy [J Antimicrob Chemother] 2018 Jan 01; Vol. 73 (1), pp. 88-94.
DOI:	10.1093/jac/dkx345
Abstrakt:	Objectives: In Klebsiella pneumoniae, overproduction of RamA results in reduced envelope permeability and reduced antimicrobial susceptibility but clinically relevant resistance is rarely observed. Here we have tested whether RamA overproduction can enhance acquired β-lactam resistance mechanisms in K. pneumoniae and have defined the envelope protein abundance changes upon RamA overproduction during growth in low and high osmolarity media. Methods: Envelope permeability was estimated using a fluorescent dye accumulation assay. β-Lactam susceptibility was measured using disc testing. Total envelope protein production was quantified using LC-MS/MS proteomics and transcript levels were quantified using real-time RT-PCR. Results: RamA overproduction enhanced β-lactamase-mediated β-lactam resistance, in some cases dramatically, without altering β-lactamase production. It increased production of efflux pumps and decreased OmpK35 porin production, though micF overexpression showed that OmpK35 reduction has little impact on envelope permeability. A survey of K. pneumoniae bloodstream isolates revealed ramA hyperexpression in 3 of 4 carbapenemase producers, 1 of 21 CTX-M producers and 2 of 19 strains not carrying CTX-M or carbapenemases. Conclusions: Whilst RamA is not a key mediator of antibiotic resistance in K. pneumoniae on its own, it is potentially important for enhancing the spectrum of acquired β-lactamase-mediated β-lactam resistance. LC-MS/MS proteomics analysis has revealed that this enhancement is achieved predominantly through activation of efflux pump production. (© The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)
Databáze:	MEDLINE
Externí odkaz:	Zobrazit plný text záznamu