TY - JOUR
T1 - Resistance to ceftazidime-avibactam is due to transposition of KPC in a porin-deficient strain of Klebsiella pneumoniae with increased efflux activity
AU - Nelson, Kirk
AU - Hemarajata, Peera
AU - Sun, Dongxu
AU - Rubio-Aparicio, Debora
AU - Tsivkovski, Ruslan
AU - Yang, Shangxin
AU - Sebra, Robert
AU - Kasarskis, Andrew
AU - Nguyen, Hoan
AU - Hanson, Blake M.
AU - Leopold, Shana
AU - Weinstock, George
AU - Lomovskaya, Olga
AU - Humphries, Romney M.
N1 - Publisher Copyright:
© 2017 American Society for Microbiology. All Rights Reserved.
PY - 2017
Y1 - 2017
N2 - Ceftazidime-avibactam is an antibiotic with activity against serine beta-lactamases, including Klebsiella pneumoniae carbapenemase (KPC). Recently, reports have emerged of KPC-producing isolates resistant to this antibiotic, including a report of a wild-type KPC-3 producing sequence type 258 Klebsiella pneumoniae that was resistant to ceftazidime-avibactam. We describe a detailed analysis of this isolate, in the context of two other closely related KPC-3 producing isolates, recovered from the same patient. Both isolates encoded a nonfunctional OmpK35, whereas we demonstrate that a novel T333N mutation in OmpK36, present in the ceftazidime-avibactam resistant isolate, reduced the activity of this porin and impacted ceftazidime-avibactam susceptibility. In addition, we demonstrate that the increased expression of blaKPC-3 and blaSHV-12 observed in the ceftazidime-avibactam-resistant isolate was due to transposition of the Tn4401 transposon harboring blaKPC-3 into a second plasmid, pIncX3, which also harbored blaSHV-12, ultimately resulting in a higher copy number of blaKPC-3 in the resistant isolate. pIncX3 plasmid from the ceftazidime-avibactam resistant isolate, conjugated into a OmpK35/36-deficient K. pneumoniae background that harbored a mutation to the ramR regulator of the acrAB efflux operon recreated the ceftazidime-avibactam-resistant MIC of 32 g/ml, confirming that this constellation of mutations is responsible for the resistance phenotype.
AB - Ceftazidime-avibactam is an antibiotic with activity against serine beta-lactamases, including Klebsiella pneumoniae carbapenemase (KPC). Recently, reports have emerged of KPC-producing isolates resistant to this antibiotic, including a report of a wild-type KPC-3 producing sequence type 258 Klebsiella pneumoniae that was resistant to ceftazidime-avibactam. We describe a detailed analysis of this isolate, in the context of two other closely related KPC-3 producing isolates, recovered from the same patient. Both isolates encoded a nonfunctional OmpK35, whereas we demonstrate that a novel T333N mutation in OmpK36, present in the ceftazidime-avibactam resistant isolate, reduced the activity of this porin and impacted ceftazidime-avibactam susceptibility. In addition, we demonstrate that the increased expression of blaKPC-3 and blaSHV-12 observed in the ceftazidime-avibactam-resistant isolate was due to transposition of the Tn4401 transposon harboring blaKPC-3 into a second plasmid, pIncX3, which also harbored blaSHV-12, ultimately resulting in a higher copy number of blaKPC-3 in the resistant isolate. pIncX3 plasmid from the ceftazidime-avibactam resistant isolate, conjugated into a OmpK35/36-deficient K. pneumoniae background that harbored a mutation to the ramR regulator of the acrAB efflux operon recreated the ceftazidime-avibactam-resistant MIC of 32 g/ml, confirming that this constellation of mutations is responsible for the resistance phenotype.
KW - Ceftazidime-avibactam
KW - KPC
KW - Klebsiella pneumoniae
KW - Porin mutation
KW - Resistance
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U2 - 10.1128/AAC.00989-17
DO - 10.1128/AAC.00989-17
M3 - Article
C2 - 28739787
AN - SCOPUS:85029764386
SN - 0066-4804
VL - 61
JO - Antimicrobial Agents and Chemotherapy
JF - Antimicrobial Agents and Chemotherapy
IS - 10
ER -