Journal article

Plazomicin activity against polymyxin-resistant Enterobacteriaceae, including MCR-1-producing isolates.

  • Denervaud-Tendon V Emerging Antibiotic Resistance, Medical and Molecular Microbiology Unit, Department of Medicine, University of Fribourg, Fribourg, Switzerland.
  • Poirel L Emerging Antibiotic Resistance, Medical and Molecular Microbiology Unit, Department of Medicine, University of Fribourg, Fribourg, Switzerland.
  • Connolly LE Achaogen, Inc., South San Francisco, CA, USA.
  • Krause KM Achaogen, Inc., South San Francisco, CA, USA.
  • Nordmann P Emerging Antibiotic Resistance, Medical and Molecular Microbiology Unit, Department of Medicine, University of Fribourg, Fribourg, Switzerland.
  • 2017-11-02
Published in:
  • The Journal of antimicrobial chemotherapy. - 2017
English Objectives
Plazomicin, a novel aminoglycoside with in vitro activity against MDR Gram-negative organisms, is under development to treat patients with serious enterobacterial infections. We evaluated the activity of plazomicin and comparators against colistin-resistant enterobacterial isolates.


Methods
Susceptibility to plazomicin and comparators was tested by broth microdilution for a collection of 95 colistin-resistant enterobacterial isolates collected from 29 hospitals in eight countries. Forty-two isolates (Klebsiella pneumoniae and Klebsiella oxytoca) possessed chromosomally encoded resistance mechanisms to colistin, 21 isolates (Escherichia coli and Salmonella enterica) expressed the mcr-1 gene, 8 isolates (Serratia, Proteus, Morganella and Hafnia) were intrinsically resistant to colistin and 24 isolates (K. pneumoniae, E. coli and Enterobacter spp.) had undefined, non-mcr-1 mechanisms. Susceptibility profiles were defined according to CLSI for aminoglycosides and to EUCAST for colistin and tigecycline.


Results
Plazomicin inhibited 89.5% and 93.7% of the colistin-resistant enterobacterial isolates at ≤ 2 and ≤4 mg/L, respectively. MICs of plazomicin were ≤2 mg/L for all of the mcr-1 positive isolates and ≤4 mg/L for all the intrinsic colistin-resistant Enterobacteriaceae. Non-susceptibility to currently marketed aminoglycosides was common: amikacin, 16.8%; gentamicin, 47.4%; and tobramycin, 63.2%. Plazomicin was the most potent aminoglycoside tested with an MIC90 of 4 mg/L, compared with 32, >64 and 64 mg/L for amikacin, gentamicin and tobramycin, respectively.


Conclusions
Plazomicin displayed potent activity against colistin-resistant clinical enterobacterial isolates, including those expressing the mcr-1 gene. Plazomicin was more active than other aminoglycosides against this collection of isolates. The further development of plazomicin for the treatment of infections due to MDR Enterobacteriaceae is warranted.
Language
  • English
Open access status
bronze
Identifiers
Persistent URL
https://sonar.ch/global/documents/165499
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