Dataset Information

Distribution of ?-Lactamase Genes and Genetic Context of bla _KPC-2 in Clinical Carbapenemase-Producing Klebsiella pneumoniae Isolates.

ABSTRACT:

Background

This study was designed to characterize the dissemination mechanism and genetic context of Klebsiella pneumoniae carbapenemase (KPC) genes in carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates.

Methods

A retrospective analysis was performed on CRKP strains isolated from a teaching hospital of Wenzhou Medical University during 2015-2017. Polymerase chain reaction (PCR)-based amplification and whole-genome sequencing (WGS) were used to analyze the genetic context of the bla _KPC-2 gene. Conjugation experiments were performed to evaluate the transferability of bla _KPC-2-bearing plasmids. Multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) were performed to investigate the clonal relatedness of bla _KPC-2-producing strains.

Results

The bla _KPC-2 gene was identified from 13.61% (40/294) of clinical K. pneumoniae isolates. Three different sequence types (ST11, ST15 and ST656) and 5 PFGE subtypes (A to E) were classified among them. ST11 was the dominant sequence type (92.50%, 37/40). Plasmid-oriented antibiotic resistance genes, such as extended spectrum-?-lactamases (ESBLs) and other antimicrobial resistance genes, were also found in KPC-positive K. pneumoniae (KPC-Kp) isolates. Mapping PCR and genomic sequencing revealed that the bla _KPC-2-bearing sequence regions, which are related to different mobile elements, including Tn1721- and IS26-based transposons, were mainly located in but not restricted to IncFII-like plasmids and were structurally divergent.

Conclusion

The bla _KPC-2 genes related to divergent mobile genetic elements encoded on transferable plasmids may transfer widely, facilitating the spread of carbapenem resistance among bacteria with different genetic backgrounds. The dissemination of bla _KPC-bearing plasmids that collectively carry additional multidrug resistance genes has caused widespread public concern, further limiting the antibiotics available to treat infections caused by KPC-producing pathogens.

SUBMITTER: Liu H

PROVIDER: S-EPMC7847768 | biostudies-literature | 2021

REPOSITORIES: biostudies-literature

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Publications

Distribution of β-Lactamase Genes and Genetic Context of <i>bla</i> <sub>KPC-2</sub> in Clinical Carbapenemase-Producing <i>Klebsiella pneumoniae</i> Isolates.

Liu Hongmao H Lin Hailong H Sun Zhewei Z Zhu Xinyi X Zhang Xueya X Li Qiaoling Q Lu Junwan J Lin Xi X Lin Li L Li Kewei K Zhu Mei M Bao Qiyu Q Xu Teng T Hu Yunliang Y Zhang Hailin H

Infection and drug resistance 20210126

<h4>Background</h4>This study was designed to characterize the dissemination mechanism and genetic context of <i>Klebsiella pneumoniae</i> carbapenemase (KPC) genes in carbapenem-resistant <i>Klebsiella pneumoniae</i> (CRKP) isolates.<h4>Methods</h4>A retrospective analysis was performed on CRKP strains isolated from a teaching hospital of Wenzhou Medical University during 2015-2017. Polymerase chain reaction (PCR)-based amplification and whole-genome sequencing (WGS) were used to analyze the ge ...[more]

PMID: 33536766

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Project description:Ceftazidime-avibactam (CZA) therapy has significantly improved survival rates for patients infected by carbapenem-resistant bacteria, including KPC producers. However, resistance to CZA is a growing concern, attributed to multiple mechanisms. In this study, we characterized four clinical CZA-resistant Klebsiella pneumoniae isolates obtained between July 2019 and December 2020. These isolates expressed novel allelic variants of blaKPC-2 resulting from changes in hotspots of the mature protein, particularly in loops surrounding the active site of KPC. Notably, KPC-80 had an K269_D270insPNK mutation near the Lys270-loop, KPC-81 had a del_I173 mutation within the Ω-loop, KPC-96 showed a Y241N substitution within the Val240-loop and KPC-97 had an V277_I278insNSEAV mutation within the Lys270-loop. Three of the four isolates exhibited low-level resistance to imipenem (4 µg/mL), while all remained susceptible to meropenem. Avibactam and relebactam effectively restored carbapenem susceptibility in resistant isolates. Cloning mutant blaKPC genes into pMBLe increased imipenem MICs in recipient Escherichia coli TOP10 for blaKPC-80, blaKPC-96, and blaKPC-97 by two dilutions; again, these MICs were restored by avibactam and relebactam. Frameshift mutations disrupted ompK35 in three isolates. Additional resistance genes, including blaTEM-1, blaOXA-18 and blaOXA-1, were also identified. Interestingly, three isolates belonged to clonal complex 11 (ST258 and ST11) and one to ST629. This study highlights the emergence of CZA resistance including unique allelic variants of blaKPC-2 and impermeability. Comprehensive epidemiological surveillance and in-depth molecular studies are imperative for understanding and monitoring these complex resistance mechanisms, crucial for effective antimicrobial treatment strategies.ImportanceThe emergence of ceftazidime-avibactam (CZA) resistance poses a significant threat to the efficacy of this life-saving therapy against carbapenem-resistant bacteria, particularly Klebsiella pneumoniae-producing KPC enzymes. This study investigates four clinical isolates exhibiting resistance to CZA, revealing novel allelic variants of the key resistance gene, blaKPC-2. The mutations identified in hotspots surrounding the active site of KPC, such as K269_D270insPNK, del_I173, Y241N and V277_I278insNSEAV, prove the adaptability of these pathogens. Intriguingly, low-level resistance to imipenem and disruptions in porin genes were observed, emphasizing the complexity of the resistance mechanisms. Interestingly, three of four isolates belonged to clonal complex 11. This research not only sheds light on the clinical significance of CZA resistance but also shows the urgency for comprehensive surveillance and molecular studies to inform effective antimicrobial treatment strategies in the face of evolving bacterial resistance.

Dataset Information

Distribution of ?-Lactamase Genes and Genetic Context of bla _KPC-2 in Clinical Carbapenemase-Producing Klebsiella pneumoniae Isolates.

Background

Methods

Results

Conclusion

Publications

Distribution of β-Lactamase Genes and Genetic Context of <i>bla</i> <sub>KPC-2</sub> in Clinical Carbapenemase-Producing <i>Klebsiella pneumoniae</i> Isolates.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

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Dataset Information

Distribution of ?-Lactamase Genes and Genetic Context of bla KPC-2 in Clinical Carbapenemase-Producing Klebsiella pneumoniae Isolates.

Background

Methods

Results

Conclusion

Publications

Distribution of β-Lactamase Genes and Genetic Context of <i>bla</i> <sub>KPC-2</sub> in Clinical Carbapenemase-Producing <i>Klebsiella pneumoniae</i> Isolates.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Distribution of ?-Lactamase Genes and Genetic Context of bla _KPC-2 in Clinical Carbapenemase-Producing Klebsiella pneumoniae Isolates.