Emergence and characterization of IncFII/IncR plasmids with multiple 5,692 bp- blaKPC−2-bearing tandem repeats in ceftazidime/avibactam non-susceptible Klebsiella pneumoniae strains

Ceftazidime/avibactam (CAZ/AVI) is widely recognized as an effective treatment for infections caused by KPC-producing Klebsiella pneumoniae (KPC-Kp). However, the prevalence of CAZ/AVI resistance among KPC-Kp isolates has increased rapidly in recent years. In this study, high-level carbapenem resist...

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Main Authors: Hongmao Liu, Mei Zhu, Junwan Lu, Shan Wu, Rujian Ye, Wei Pan, Yirong Li, Qiyu Bao, Dawei Huang
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-04-01
Series:Frontiers in Microbiology
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Online Access:https://www.frontiersin.org/articles/10.3389/fmicb.2025.1534631/full
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author Hongmao Liu
Hongmao Liu
Mei Zhu
Junwan Lu
Junwan Lu
Shan Wu
Rujian Ye
Wei Pan
Yirong Li
Qiyu Bao
Qiyu Bao
Dawei Huang
author_facet Hongmao Liu
Hongmao Liu
Mei Zhu
Junwan Lu
Junwan Lu
Shan Wu
Rujian Ye
Wei Pan
Yirong Li
Qiyu Bao
Qiyu Bao
Dawei Huang
author_sort Hongmao Liu
collection DOAJ
description Ceftazidime/avibactam (CAZ/AVI) is widely recognized as an effective treatment for infections caused by KPC-producing Klebsiella pneumoniae (KPC-Kp). However, the prevalence of CAZ/AVI resistance among KPC-Kp isolates has increased rapidly in recent years. In this study, high-level carbapenem resistance and enhanced CAZ/AVI resistance were observed in two hypervirulent carbapenem-resistant K. pneumoniae isolates, KP1878 and KP3034, following prolonged carbapenem use. Virulence phenotypes were confirmed using the string test and a Galleria mellonella larvae infection model. Real-time quantitative PCR revealed that the relative expression of blaKPC−2 in KP1878 and KP3034 was 2.4-fold and 11.6-fold higher, respectively, than that in the CAZ/AVI-susceptible KPC-Kp strain KP1880. Whole-genome sequencing showed that the blaKPC−2 gene resided within an identical 5,692-bp ΔklcA-korC-ΔISKpn6-blaKPC−2-ISKpn8-ΔtnpR-IS26 tandem repeat, which was replicated twice and four times in plasmids pKPC1878 and pKPC3034, respectively. Compared with KP1880, the β-lactamase hydrolysis activities of crude cell lysates derived from KP1878 and KP3034 were significantly higher in their ability to hydrolyze meropenem, ceftazidime, and nitrocefin. S1-nuclease-digested pulsed-field gel electrophoresis, along with Southern blot and restriction fragment length polymorphism fingerprinting, identified plasmid profiles but revealed one or more 5.6-kilobase variations in the regions hybridized with the KPC-specific probe. Further comparative genomic analysis suggested that a potential homologous recombination event occurred between the blaKPC−2-carrying plasmid and the pLVPK-like virulence plasmid of KP3034, leading to the generation of a cointegrated plasmid that combined both virulence and CAZ/AVI resistance.
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series Frontiers in Microbiology
spelling doaj-art-b7e99c1b293b48c8a28adf00a2f60a792025-08-20T03:03:03ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2025-04-011610.3389/fmicb.2025.15346311534631Emergence and characterization of IncFII/IncR plasmids with multiple 5,692 bp- blaKPC−2-bearing tandem repeats in ceftazidime/avibactam non-susceptible Klebsiella pneumoniae strainsHongmao Liu0Hongmao Liu1Mei Zhu2Junwan Lu3Junwan Lu4Shan Wu5Rujian Ye6Wei Pan7Yirong Li8Qiyu Bao9Qiyu Bao10Dawei Huang11Department of Laboratory Medicine, Zhongnan Hospital of Wuhan University, Wuhan, ChinaSchool of Laboratory Medicine and Life Sciences, Institue of Biomedical Informatics, Wenzhou Medical University, Wenzhou, ChinaDepartment of Clinical Laboratory, Zhejiang Hospital, Hangzhou, ChinaSchool of Laboratory Medicine and Life Sciences, Institue of Biomedical Informatics, Wenzhou Medical University, Wenzhou, ChinaMedical Molecular Biology Laboratory, School of Medicine, Jinhua University of Vocational Technology, Jinhua, ChinaDepartment of Clinical Laboratory, The People's Hospital of Yuhuan, Taizhou, ChinaDepartment of Clinical Laboratory, The People's Hospital of Yuhuan, Taizhou, ChinaDepartment of Clinical Laboratory, The People's Hospital of Yuhuan, Taizhou, ChinaDepartment of Laboratory Medicine, Zhongnan Hospital of Wuhan University, Wuhan, ChinaSchool of Laboratory Medicine and Life Sciences, Institue of Biomedical Informatics, Wenzhou Medical University, Wenzhou, ChinaMedical Molecular Biology Laboratory, School of Medicine, Jinhua University of Vocational Technology, Jinhua, ChinaDepartment of Clinical Laboratory, The People's Hospital of Yuhuan, Taizhou, ChinaCeftazidime/avibactam (CAZ/AVI) is widely recognized as an effective treatment for infections caused by KPC-producing Klebsiella pneumoniae (KPC-Kp). However, the prevalence of CAZ/AVI resistance among KPC-Kp isolates has increased rapidly in recent years. In this study, high-level carbapenem resistance and enhanced CAZ/AVI resistance were observed in two hypervirulent carbapenem-resistant K. pneumoniae isolates, KP1878 and KP3034, following prolonged carbapenem use. Virulence phenotypes were confirmed using the string test and a Galleria mellonella larvae infection model. Real-time quantitative PCR revealed that the relative expression of blaKPC−2 in KP1878 and KP3034 was 2.4-fold and 11.6-fold higher, respectively, than that in the CAZ/AVI-susceptible KPC-Kp strain KP1880. Whole-genome sequencing showed that the blaKPC−2 gene resided within an identical 5,692-bp ΔklcA-korC-ΔISKpn6-blaKPC−2-ISKpn8-ΔtnpR-IS26 tandem repeat, which was replicated twice and four times in plasmids pKPC1878 and pKPC3034, respectively. Compared with KP1880, the β-lactamase hydrolysis activities of crude cell lysates derived from KP1878 and KP3034 were significantly higher in their ability to hydrolyze meropenem, ceftazidime, and nitrocefin. S1-nuclease-digested pulsed-field gel electrophoresis, along with Southern blot and restriction fragment length polymorphism fingerprinting, identified plasmid profiles but revealed one or more 5.6-kilobase variations in the regions hybridized with the KPC-specific probe. Further comparative genomic analysis suggested that a potential homologous recombination event occurred between the blaKPC−2-carrying plasmid and the pLVPK-like virulence plasmid of KP3034, leading to the generation of a cointegrated plasmid that combined both virulence and CAZ/AVI resistance.https://www.frontiersin.org/articles/10.3389/fmicb.2025.1534631/fullKlebsiella pneumoniaeCeftazidime/avibactamblaKPC-2hypervirulent5,692 bp-tandem repeat
spellingShingle Hongmao Liu
Hongmao Liu
Mei Zhu
Junwan Lu
Junwan Lu
Shan Wu
Rujian Ye
Wei Pan
Yirong Li
Qiyu Bao
Qiyu Bao
Dawei Huang
Emergence and characterization of IncFII/IncR plasmids with multiple 5,692 bp- blaKPC−2-bearing tandem repeats in ceftazidime/avibactam non-susceptible Klebsiella pneumoniae strains
Frontiers in Microbiology
Klebsiella pneumoniae
Ceftazidime/avibactam
blaKPC-2
hypervirulent
5,692 bp-tandem repeat
title Emergence and characterization of IncFII/IncR plasmids with multiple 5,692 bp- blaKPC−2-bearing tandem repeats in ceftazidime/avibactam non-susceptible Klebsiella pneumoniae strains
title_full Emergence and characterization of IncFII/IncR plasmids with multiple 5,692 bp- blaKPC−2-bearing tandem repeats in ceftazidime/avibactam non-susceptible Klebsiella pneumoniae strains
title_fullStr Emergence and characterization of IncFII/IncR plasmids with multiple 5,692 bp- blaKPC−2-bearing tandem repeats in ceftazidime/avibactam non-susceptible Klebsiella pneumoniae strains
title_full_unstemmed Emergence and characterization of IncFII/IncR plasmids with multiple 5,692 bp- blaKPC−2-bearing tandem repeats in ceftazidime/avibactam non-susceptible Klebsiella pneumoniae strains
title_short Emergence and characterization of IncFII/IncR plasmids with multiple 5,692 bp- blaKPC−2-bearing tandem repeats in ceftazidime/avibactam non-susceptible Klebsiella pneumoniae strains
title_sort emergence and characterization of incfii incr plasmids with multiple 5 692 bp blakpc 2 bearing tandem repeats in ceftazidime avibactam non susceptible klebsiella pneumoniae strains
topic Klebsiella pneumoniae
Ceftazidime/avibactam
blaKPC-2
hypervirulent
5,692 bp-tandem repeat
url https://www.frontiersin.org/articles/10.3389/fmicb.2025.1534631/full
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