Role of AmpG in the resistance to β-lactam agents, including cephalosporins and carbapenems: candidate for a novel antimicrobial target

Roshan D’Souza, Le Phuong Nguyen, Naina A. Pinto, Hyunsook Lee, Thao Nguyen Vu, Hoyoung Kim, Hyun Soo Cho, Dongeun Yong

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1 Citation (Scopus)


Background: A complex cascade of genes, enzymes, and transcription factors regulates AmpC β-lactamase overexpression. We investigated the network of AmpC β-lactamase overexpression in Klebsiella aerogenes and identified the role of AmpG in resistance to β-lactam agents, including cephalosporins and carbapenems. Methods: A transposon mutant library was created for carbapenem-resistant K. aerogenes YMC2008-M09-943034 (KE-Y1) to screen for candidates with increased susceptibility to carbapenems, which identified the susceptible mutant derivatives KE-Y3 and KE-Y6. All the strains were subjected to highly contiguous de novo assemblies using PacBio sequencing to investigate the loss of resistance due to transposon insertion. Complementation and knock-out experiments using lambda Red-mediated homologous recombinase and CRISPR–Cas9 were performed to confirm the role of gene of interest. Results: In-depth analysis of KE-Y3 and KE-Y6 revealed the insertion of a transposon at six positions in each strain, at which truncation of the AmpG permease gene was common in both. The disruption of the AmpG permease leads to carbapenem susceptibility, which was further confirmed by complementation. We generated an AmpG permease gene knockout using lambda Red-mediated recombineering in K. aerogenes KE-Y1 and a CRISPR–Cas9-mediated gene knockout in multidrug-resistant Klebsiella pneumoniae-YMC/2013/D to confer carbapenem susceptibility. Conclusions: These findings suggest that inhibition of the AmpG is a potential strategy to increase the efficacy of β-lactam agents against Klebsiella aerogenes.

Original languageEnglish
Article number45
JournalAnnals of Clinical Microbiology and Antimicrobials
Issue number1
Publication statusPublished - 2021 Dec

Bibliographical note

Funding Information:
This work was supported by the BioNano Health-Guard Research Center funded by the Ministry of Science, ICT & Future Planning (MSIP) of Korea as a Global Frontier Project (H-GUARD_2014M3A6B2060509); the Research Program funded by the Korea Centers for Disease Control and Prevention(2019-ER5403-00); a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (Grant Number: HI14C1324). This work was also supported by the Brain Korea 21 PLUS Project for Medical Science, Yonsei University.

Publisher Copyright:
© 2021, The Author(s).

All Science Journal Classification (ASJC) codes

  • Microbiology (medical)
  • Infectious Diseases


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