View in EDS HTML Full Text PDF Full Text

Characterization of the impact of rpoB mutations on the in vitro and in vivo competitive fitness of Clostridium difficile and susceptibility to fidaxomicin.

Saved in:
Bibliographic Details
Title: Characterization of the impact of rpoB mutations on the in vitro and in vivo competitive fitness of Clostridium difficile and susceptibility to fidaxomicin.
Authors: Kuehne, Sarah A1, Dempster, Andrew W2, Collery, Mark M2, Joshi, Nimitray2, Jowett, Jamie2, Kelly, Michelle L2, Cave, Rory2, Longshaw, Chris M3, Minton, Nigel P4 nigel.minton@nottingham.ac.uk
Source: Journal of Deaf Studies & Deaf Education. Apr2018, Vol. 23 Issue 2, p973-980. 8p.
Subject Terms: Alleles, Clostridioides difficile, Clostridium diseases, Disease susceptibility, Erythromycin, Genetic polymorphisms, Microbial sensitivity tests, Genetic mutation, Transferases, Microbial virulence, Sequence analysis, In vitro studies, Fidaxomicin, In vivo studies, Pharmacodynamics, Therapeutics
Abstract: Objectives: To establish the role of specific, non-synonymous SNPs in the RNA polymerase β subunit (rpoB) gene in reducing the susceptibility of Clostridium difficile to fidaxomicin and to explore the potential in vivo significance of rpoB mutant strains.Methods: Allelic exchange was used to introduce three different SNPs into the rpoB gene of an erythromycin-resistant derivative (CRG20291) of C. difficile R20291. The genome sequences of the created mutants were determined and each mutant analysed with respect to growth and sporulation rates, toxin A/B production and cytotoxicity against Vero cells, and in competition assays. Their comparative virulence and colonization ability was also assessed in a hamster infection model.Results: The MIC of fidaxomicin displayed by three mutants CRG20291-TA, CRG20291-TG and CRG20291-GT was substantially increased (>32, 8 and 2 mg/L, respectively) relative to that of the parent strain (0.25 mg/L). Genome sequencing established that the intended mutagenic substitutions in rpoB were the only changes present. Relative to CRG20291, all mutants had attenuated growth, were outcompeted by the parental strain, had lower sporulation and toxin A/B production capacities, and displayed diminished cytotoxicity. In a hamster model, virulence of all three mutants was significantly reduced compared with the progenitor strain, whereas the degree of caecum colonization was unaltered.Conclusions: Our study demonstrates that particular SNPs in rpoB lead to reduced fidaxomicin susceptibility. These mutations were associated with a fitness cost in vitro and reduced virulence in vivo. [ABSTRACT FROM AUTHOR]
Copyright of Journal of Deaf Studies & Deaf Education is the property of Oxford University Press / USA and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Education Research Complete
Full text is not displayed to guests.
Description
Abstract:<bold>Objectives: </bold>To establish the role of specific, non-synonymous SNPs in the RNA polymerase β subunit (rpoB) gene in reducing the susceptibility of Clostridium difficile to fidaxomicin and to explore the potential in vivo significance of rpoB mutant strains.<bold>Methods: </bold>Allelic exchange was used to introduce three different SNPs into the rpoB gene of an erythromycin-resistant derivative (CRG20291) of C. difficile R20291. The genome sequences of the created mutants were determined and each mutant analysed with respect to growth and sporulation rates, toxin A/B production and cytotoxicity against Vero cells, and in competition assays. Their comparative virulence and colonization ability was also assessed in a hamster infection model.<bold>Results: </bold>The MIC of fidaxomicin displayed by three mutants CRG20291-TA, CRG20291-TG and CRG20291-GT was substantially increased (>32, 8 and 2 mg/L, respectively) relative to that of the parent strain (0.25 mg/L). Genome sequencing established that the intended mutagenic substitutions in rpoB were the only changes present. Relative to CRG20291, all mutants had attenuated growth, were outcompeted by the parental strain, had lower sporulation and toxin A/B production capacities, and displayed diminished cytotoxicity. In a hamster model, virulence of all three mutants was significantly reduced compared with the progenitor strain, whereas the degree of caecum colonization was unaltered.<bold>Conclusions: </bold>Our study demonstrates that particular SNPs in rpoB lead to reduced fidaxomicin susceptibility. These mutations were associated with a fitness cost in vitro and reduced virulence in vivo. [ABSTRACT FROM AUTHOR]
ISSN:10814159
DOI:10.1093/jac/dkx486