Emergence of Ceftazidime-Avibactam Resistance Due to Plasmid-Borne blaKPC-3 Mutations during Treatment of Carbapenem-Resistant Klebsiella pneumoniae Infections

Antimicrob Agents Chemother. 2017 Feb 23;61(3):e02097-16. doi: 10.1128/AAC.02097-16. Print 2017 Mar.


Ceftazidime-avibactam is a novel β-lactam/β-lactamase inhibitor with activity against carbapenem-resistant Enterobacteriaceae (CRE) that produce Klebsiella pneumoniae carbapenemase (KPC). We report the first cases of ceftazidime-avibactam resistance to develop during treatment of CRE infections and identify resistance mechanisms. Ceftazidime-avibactam-resistant K. pneumoniae emerged in three patients after ceftazidime-avibactam treatment for 10 to 19 days. Whole-genome sequencing (WGS) of longitudinal ceftazidime-avibactam-susceptible and -resistant K. pneumoniae isolates was used to identify potential resistance mechanisms. WGS identified mutations in plasmid-borne blaKPC-3, which were not present in baseline isolates. blaKPC-3 mutations emerged independently in isolates of a novel sequence type 258 sublineage and resulted in variant KPC-3 enzymes. The mutations were validated as resistance determinants by measuring MICs of ceftazidime-avibactam and other agents following targeted gene disruption in K. pneumoniae, plasmid transfer, and blaKPC cloning into competent Escherichia coli In rank order, the impact of KPC-3 variants on ceftazidime-avibactam MICs was as follows: D179Y/T243M double substitution > D179Y > V240G. Remarkably, mutations reduced meropenem MICs ≥4-fold from baseline, restoring susceptibility in K. pneumoniae from two patients. Cefepime and ceftriaxone MICs were also reduced ≥4-fold against D179Y/T243M and D179Y variant isolates, but susceptibility was not restored. Reverse transcription-PCR revealed that expression of blaKPC-3 encoding D179Y/T243M and D179Y variants was diminished compared to blaKPC-3 expression in baseline isolates. In conclusion, the development of resistance-conferring blaKPC-3 mutations in K. pneumoniae within 10 to 19 days of ceftazidime-avibactam exposure is troubling, but clinical impact may be ameliorated if carbapenem susceptibility is restored in certain isolates.

Keywords: Klebsiella pneumoniae; Klebsiella pneumoniae carbapenemase; carbapenem-resistant Enterobacteriaceae; ceftazidime-avibactam; resistance; sequence type 258.

Publication types

  • Case Reports

MeSH terms

  • Aged
  • Amino Acid Substitution
  • Anti-Bacterial Agents / pharmacology*
  • Azabicyclo Compounds / pharmacology*
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism
  • Cefepime
  • Ceftazidime / pharmacology*
  • Ceftriaxone / pharmacology
  • Cephalosporins / pharmacology
  • Cloning, Molecular
  • Drug Combinations
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Female
  • Gene Expression
  • Genome, Bacterial*
  • High-Throughput Nucleotide Sequencing
  • Humans
  • Klebsiella Infections / drug therapy
  • Klebsiella Infections / microbiology*
  • Klebsiella pneumoniae / drug effects
  • Klebsiella pneumoniae / genetics*
  • Klebsiella pneumoniae / growth & development
  • Klebsiella pneumoniae / isolation & purification
  • Male
  • Meropenem
  • Microbial Sensitivity Tests
  • Middle Aged
  • Mutation
  • Plasmids / chemistry
  • Plasmids / metabolism
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Thienamycins / pharmacology
  • beta-Lactam Resistance / genetics*
  • beta-Lactamases / genetics*
  • beta-Lactamases / metabolism


  • Anti-Bacterial Agents
  • Azabicyclo Compounds
  • Bacterial Proteins
  • Cephalosporins
  • Drug Combinations
  • Recombinant Proteins
  • Thienamycins
  • avibactam, ceftazidime drug combination
  • Ceftriaxone
  • Cefepime
  • Ceftazidime
  • beta-Lactamases
  • beta-lactamase KPC-3, Klebsiella pneumoniae
  • Meropenem