Association of the novel aminoglycoside resistance determinant RmtF with NDM carbapenemase in Enterobacteriaceae isolated in India and the UK

Laura Hidalgo, Katie L Hopkins, Belen Gutierrez, Cristina M Ovejero, Suruchi Shukla, Stephen Roger Douthwaite, Kashi N Prasad, Neil Woodford, Bruno Gonzalez-Zorn

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Objectives: 16S rRNA methyltransferases are an emerging mechanism conferring high-level resistance to clinically relevant aminoglycosides and have been associated with important mechanisms such as NDM-1. We sought genes encoding these enzymes in isolates highly resistant (MIC > 200 mg/L) to gentamicin and amikacin from an Indian hospital and we additionally screened for the novel RmtF enzyme in 132 UK isolates containing NDM. Methods: All highly aminoglycoside-resistant isolates were screened for armA and rmtA-E by PCR, with cloning experiments performed for isolates negative for these genes. Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry was used to determine the methylation target of the novel RmtF methyltransferase. RmtF-bearing strains were characterized further, including susceptibility testing, PFGE, electroporation, PCR-based replicon typing and multilocus sequence typing of rmtF-bearing plasmids. Results: High-level aminoglycoside resistance was detected in 140/1000 (14%) consecutive isolates of Enterobacteriaceae from India. ArmA, RmtB and RmtC were identified among 46%, 20% and 27% of these isolates, respectively. The novel rmtF gene was detected in 34 aminoglycoside-resistant isolates (overall prevalence 3.4%), most (59%) of which also possessed a bla NDM gene; rmtF was detected in 6 NDM producers from the UK. It was found on different plasmid backbones. Four and two isolates showed resistance to tigecycline and colistin, respectively. Conclusions: RmtF was often found in association with NDM in members of the Enterobacteriaceae and on diverse plasmids. It is of clinical concern that the RmtF- and NDM-positive strains identified here show additional resistance to tigecycline and colistin, current drugs of last resort for the treatment of serious bacterial infections.

Original languageEnglish
JournalJournal of Antimicrobial Chemotherapy
Volume68
Issue number7
Pages (from-to)1543-1550
ISSN0305-7453
DOIs
Publication statusPublished - 2013

Keywords

  • 16S rRNA methyltransferases
  • Resistance
  • antimicrobial

Fingerprint

Dive into the research topics of 'Association of the novel aminoglycoside resistance determinant RmtF with NDM carbapenemase in Enterobacteriaceae isolated in India and the UK'. Together they form a unique fingerprint.

Cite this