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ORIGINAL RESEARCH article

Front. Cell. Infect. Microbiol.
Sec. Antibiotic Resistance and New Antimicrobial drugs
Volume 14 - 2024 | doi: 10.3389/fcimb.2024.1435123
This article is part of the Research Topic Evolution, Molecular Mechanisms and the Strategies to Combat Antimicrobial Resistance (AMR): A One Health Approach View all 19 articles

APH(3')-Ie, an aminoglycoside-modifying enzyme discovered in an rabbit-derived Citrobacter gillenii isolate

Provisionally accepted
Naru Lin Naru Lin 1,2Yuning Sha Yuning Sha 1Guozhi Zhang Guozhi Zhang 1Chunhan Song Chunhan Song 3*Yuan Zhang Yuan Zhang 1Jingxuan Zhao Jingxuan Zhao 1Dawei Huang Dawei Huang 4*Junwan Lu Junwan Lu 3Qiyu Bao Qiyu Bao 1,2,3*Wei Pan Wei Pan 4*
  • 1 Institute of Bioinformatics, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
  • 2 Pingyang Hospital of Wenzhou Medical University, Pingyang, China
  • 3 Medical Molecular Biology Laboratory, School of Medicine, Jinhua Polytechnic, Jinhua, Zhejiang Province, China
  • 4 The People’s Hospital of Yuhuan, Yuhuan, China

The final, formatted version of the article will be published soon.

    Background: Aminoglycoside-modifying enzymes (AMEs) play an essential role in bacterial resistance to aminoglycoside antimicrobials. With the development of sequencing techniques, more bacterial genomes have been sequenced, which has aided in the discovery of an increasing number of novel resistance mechanisms.The bacterial species was identified by 16S rRNA gene homology and average nucleotide identity (ANI) analyses. The minimum inhibitory concentration (MIC) of each antimicrobial was determined by the agar dilution method. The protein was expressed with the pCold I vector in E. coli BL21, and enzyme kinetic parameters were examined. The whole-genome sequence of the bacterium was obtained via the Illumina and PacBio sequencing platforms. Reconstruction of the phylogenetic tree, identification of conserved functional residues, and gene context analysis were performed using the corresponding bioinformatic techniques.: A novel aminoglycoside resistance gene, designated aph(3')-Ie, which confers resistance to ribostamycin, kanamycin, sisomicin and paromomycin, was identified in the chromosome of the animal bacterium Citrobacter gillenii DW61, which exhibited a multidrug resistance phenotype. APH(3')-Ie showed the highest amino acid identity of 74.90% with the functionally characterized enzyme APH(3')-Ia. Enzyme kinetics analysis demonstrated that it had phosphorylation activity toward four aminoglycoside substrates, exhibiting the highest affinity (Km, 4.22 ± 0.88 µM) and the highest catalytic efficiency [kcat/Km, (32.27±8.14)  10 4 ] for ribomycin. Similar to the other APH(3') proteins, APH(3')-Ie contained all the conserved functional sites of the APH family. The aph(3')-Ie homologous genes were present in C. gillenii isolates from different sources, including some of clinical significance. Conclusion: In this work, a novel chromosomal aminoglycoside resistance gene, designated aph(3')-Ie, conferring resistance to aminoglycoside antimicrobials, was identified in a rabbit isolate C. gillenii DW61. The elucidation of the novel resistance mechanism will aid in the effective treatment of infections caused by pathogens carrying such resistance genes.

    Keywords: Citrobacter gillenii, Resistance mechanism, aminoglycoside 3'phosphotransferase, aph(3')-Ie, Kinetic parameter

    Received: 19 May 2024; Accepted: 15 Jul 2024.

    Copyright: © 2024 Lin, Sha, Zhang, Song, Zhang, Zhao, Huang, Lu, Bao and Pan. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence:
    Chunhan Song, Medical Molecular Biology Laboratory, School of Medicine, Jinhua Polytechnic, Jinhua, Zhejiang Province, China
    Dawei Huang, The People’s Hospital of Yuhuan, Yuhuan, China
    Qiyu Bao, Pingyang Hospital of Wenzhou Medical University, Pingyang, China
    Wei Pan, The People’s Hospital of Yuhuan, Yuhuan, China

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