en
Scientific article
Open access
English

Vertical and horizontal dissemination of an incC plasmid harbouring rmtb 16s rRNA methylase gene, conferring resistance to plazomicin, among invasive ST258 and ST16 KPC-producing Klebsiella pneumoniae

Published inJournal of global antimicrobial resistance, vol. 24, p. 183-189
Publication date2021-03
Abstract

Objectives: Carbapenem resistance in Klebsiella pneumoniae is a major clinical challenge. Aminoglycosides remain an important asset in the current therapeutic arsenal to treat these infections. We examined aminoglycoside resistance phenotypes and genomics in a collection of 100 invasive KPC-producing K. pneumoniae isolates sequentially collected in a Brazilian tertiary hospital between 2014 and 2016.

Methods: Aminoglycoside susceptibility testing was performed. We used a combined long-read (MinION) and short-read (Illumina) whole-genome sequencing strategy to provide a genomic picture of aminoglycoside resistance genes, with particular emphasis on 16S rRNA methyltransferases and related plasmids.

Results: 68% of the strains were resistant to gentamicin and 42% to amikacin, with 35% resistant to both of these commonly used aminoglycosides. We identified the 16S rRNA methyltransferase gene rmtB in 30% of these isolates: 97% (29/30) belonged to sequence type 258 (ST258) and a single isolate to the emergent ST16 clone. In ST258 and ST16 the rmtB gene was located on large IncC plasmids of 177 kb and 174 kb, respectively, highly similar to a plasmid previously identified in Proteus mirabilis in the same hospital. Moreover, 99% of the isolates remained susceptible to the veterinary-approved drug apramycin, currently under clinical development for human medicine.

Conclusion: Such findings in geographically and temporally related isolates suggest a combination of vertical clonal spread as well as horizontal interspecies and intraspecies plasmid transfer. This broad rmtB dissemination in an endemic setting for KPC-producing clones is worrisome since it provides resistance to most clinically available aminoglycosides, including the novel aminoglycoside-modifying enzyme-resistant plazomicin.

eng
Keywords
  • 16S rRNA methyltransferase
  • Aminoglycosides
  • Apramycin
  • KPC-producing Klebsiella pneumoniae
  • Plazomicin
  • rmtB
Funding
Citation (ISO format)
ROCH, Mélanie et al. Vertical and horizontal dissemination of an incC plasmid harbouring <i>rmtb</i> 16s rRNA methylase gene, conferring resistance to plazomicin, among invasive ST258 and ST16 KPC-producing <i>Klebsiella pneumoniae</i>. In: Journal of global antimicrobial resistance, 2021, vol. 24, p. 183–189. doi: 10.1016/j.jgar.2020.12.006

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Creation01/24/2022 11:45:00 AM
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