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ORIGINAL RESEARCH article

Front. Microbiol.
Sec. Antimicrobials, Resistance and Chemotherapy
Volume 15 - 2024 | doi: 10.3389/fmicb.2024.1401802
This article is part of the Research Topic Global Dissemination and Evolution of Epidemic Multidrug-Resistant Gram-Negative Bacterial Pathogens: Surveillance, Diagnosis and Treatment, Volume III View all 5 articles

Two colistin resistance-producing Aeromonas strains, isolated from coastal waters in Zhejiang, China: Characteristics, multi-drug resistance and pathogenicity

Provisionally accepted
Hongxian Chen Hongxian Chen 1Fang-Jie Chen Fang-Jie Chen 1Qian-Jin ZHOU Qian-Jin ZHOU 1*Shi-Lin Shang Shi-Lin Shang 1Biao Tang Biao Tang 2Zhong-Jie Xu Zhong-Jie Xu 1Li-Jun Duan Li-Jun Duan 1Jing-Lei Jin Jing-Lei Jin 1Guizong XU Guizong XU 1Maocang Yan Maocang Yan 3Jiong Chen Jiong Chen 1*
  • 1 Ningbo University, Ningbo, Zhejiang Province, China
  • 2 Zhejiang Academy of Agricultural Sciences, Hangzhou, Zhejiang, China
  • 3 Zhejiang Mariculture Research Institute, Wenzhou, Zhejiang Province, China

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

    Aeromonas spp. are ubiquitous inhabitants of ecosystems, and many species are opportunistically pathogenic to humans and animals. Multidrug-resistant (MDR) Aeromonas species have been widely detected in hospitals, urban rivers, livestock, and aquatic animals. In this study, we identified two Aeromonas isolates, namely A. veronii 0728Q8Av and A. caviae 1029Y16Ac, from coastal waters in Zhejiang, China. Both isolates exhibited typical biochemical characteristics and conferred MDR to 11 kinds of antibiotics, remaining susceptible to ceftazidime. Whole-genome sequencing revealed that both isolates harbored multiple antibiotic resistance genes (ARGs) and several mobile genetic elements (MGEs) on the chromosomes, each containing a resistance genomic island (GI), a typical class 1 integron, a transposon, and various insertion sequences (ISs). Most ARGs were situated within the multiple resistance GI, which contained a class 1 integron and a transposon in both Aeromonas isolates. Furthermore, a chromosomal mcr-3.16 gene was identified in A. veronii 0728Q8Av, while a chromosomal mcr-3.3 was found in A. caviae 1029Y16Ac. Both mcr-3 variants were not located within but were distanced from the multidrug resistance GI on the chromosome, flanking by multiple ISs. In addition, a mcr-3-like was found adjacent to mcr-3.16 to form a tandem mcr-3.16-mcr-3-like-dgkA structure; yet, Escherichia coli carrying the recombinants of mcr-3-like did not exhibit resistance to colistin. And an incomplete mcr-3-like was found adjacent to mcr-3.3 in A. caviae 1029Y16Ac, suggesting the possibility that mcr-3 variants originated from Aeromonas species. In vivo bacterial pathogenicity test indicated that A. veronii 0728Q8Av exhibited moderate pathogenicity towards infected ayu, while A. caviae 1029Y16Ac was non-virulent. Thus, both Aeromonas species deserve further attention regarding their antimicrobial resistance and pathogenicity.

    Keywords: Aeromonas, antibiotic resistance genes, mobile genetic elements, mcr-3, pathogenicity, Coastal water

    Received: 16 Mar 2024; Accepted: 18 Jul 2024.

    Copyright: © 2024 Chen, Chen, ZHOU, Shang, Tang, Xu, Duan, Jin, XU, Yan and Chen. 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:
    Qian-Jin ZHOU, Ningbo University, Ningbo, 315211, Zhejiang Province, China
    Jiong Chen, Ningbo University, Ningbo, 315211, Zhejiang Province, China

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