title: Emergence of Ceftazidime-Avibactam Resistance Due to Plasmid-BorneblaKPC-3Mutations during Treatment of Carbapenem-Resistant Klebsiella pneumoniae Infections.
abstract: Ceftazidime-avibactam is a novel β-lactam/β-lactamase inhibitor with activity against carbapenem-resistantEnterobacteriaceae(CRE) that produceKlebsiella pneumoniaecarbapenemase (KPC). We report the first cases of ceftazidime-avibactam resistance to develop during treatment of CRE infections and identify resistance mechanisms. Ceftazidime-avibactam-resistantK. pneumoniaeemerged in three patients after ceftazidime-avibactam treatment for 10 to 19 days. Whole-genome sequencing (WGS) of longitudinal ceftazidime-avibactam-susceptible and -resistantK. pneumoniaeisolates was used to identify potential resistance mechanisms. WGS identified mutations in plasmid-borneblaKPC-3, which were not present in baseline isolates.blaKPC-3mutations 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 inK. pneumoniae, plasmid transfer, andblaKPCcloning into competentEscherichia coliIn 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 inK. pneumoniaefrom 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 ofblaKPC-3encoding D179Y/T243M and D179Y variants was diminished compared toblaKPC-3expression in baseline isolates. In conclusion, the development of resistance-conferringblaKPC-3mutations inK. pneumoniaewithin 10 to 19 days of ceftazidime-avibactam exposure is troubling, but clinical impact may be ameliorated if carbapenem susceptibility is restored in certain isolates.
authors.affiliation: Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.|XDR Pathogen Laboratory, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
authors.forename: Ryan K
authors.initials: RK
authors.lastname: Shields
authors.affiliation: Public Health Research Institute Tuberculosis Center, New Jersey Medical School, Rutgers University, Newark, New Jersey, USA.
authors.forename: Liang
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Shaoji
authors.initials: S
authors.lastname: Cheng
authors.affiliation: Public Health Research Institute Tuberculosis Center, New Jersey Medical School, Rutgers University, Newark, New Jersey, USA.
authors.forename: Kalyan D
authors.initials: KD
authors.lastname: Chavda
authors.affiliation: Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Ellen G
authors.initials: EG
authors.lastname: Press
authors.affiliation: Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Avin
authors.initials: A
authors.lastname: Snyder
authors.affiliation: Public Health Research Institute Tuberculosis Center, New Jersey Medical School, Rutgers University, Newark, New Jersey, USA.
authors.forename: Ruchi
authors.initials: R
authors.lastname: Pandey
authors.affiliation: Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Doi
authors.affiliation: Public Health Research Institute Tuberculosis Center, New Jersey Medical School, Rutgers University, Newark, New Jersey, USA.
authors.forename: Barry N
authors.initials: BN
authors.lastname: Kreiswirth
authors.affiliation: Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA mhn5@pitt.edu.|XDR Pathogen Laboratory, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
authors.forename: M Hong
authors.initials: MH
authors.lastname: Nguyen
authors.affiliation: Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.|XDR Pathogen Laboratory, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.|VA Pittsburgh Healthcare System, Pittsburgh, Pennsylvania, USA.
authors.forename: Cornelius J
authors.initials: CJ
authors.lastname: Clancy
mesh_terms: D000368:Aged; D019943:Amino Acid Substitution; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D053961:Azabicyclo Compounds / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D000077723:Cefepime; D002442:Ceftazidime / Q000494:pharmacology*; D002443:Ceftriaxone / Q000494:pharmacology; D002511:Cephalosporins / Q000494:pharmacology; D003001:Cloning, Molecular; D004338:Drug Combinations; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D016680:Genome, Bacterial; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D007710:Klebsiella Infections / Q000188:drug therapy / Q000382:microbiology*; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000302:isolation & purification; D008297:Male; D000077731:Meropenem; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009154:Mutation; D010957:Plasmids / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013845:Thienamycins / Q000494:pharmacology; D018440:beta-Lactam Resistance / Q000235:genetics*; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D053961:Azabicyclo Compounds; D001426:Bacterial Proteins; D002511:Cephalosporins; D004338:Drug Combinations; D011994:Recombinant Proteins; D013845:Thienamycins; C000595613:avibactam, ceftazidime drug combination; D002443:Ceftriaxone; D000077723:Cefepime; D002442:Ceftazidime; D001618:beta-Lactamases; C495220:beta-lactamase KPC-3, Klebsiella pneumoniae; D000077731:Meropenem
keywords: Klebsiella pneumoniae; Klebsiella pneumoniae carbapenemase; carbapenem-resistant Enterobacteriaceae; ceftazidime-avibactam; resistance; sequence type 258