ORIGINAL RESEARCH article
Front. Microbiol.
Sec. Antimicrobials, Resistance and Chemotherapy
Volume 16 - 2025 | doi: 10.3389/fmicb.2025.1642708
This article is part of the Research TopicMobilome Manipulation: Engineering Microbiomes to Counteract Antimicrobial ResistanceView all articles
Emergence of Tigecycline-Resistant Raoultella ornithinolytica with tet(X)-Carrying Plasmid from Swine Wastewater in China
Provisionally accepted
- 1Laboratory Animal Centre, Wenzhou Medical University, Wenzhou, China
- 2Department of Clinical Laboratory, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
- 3Wenzhou Medical University, Wenzhou Medical University, Wenzhou, China
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Background: The increasing prevalence of antibiotic resistance genes (ARGs), such as the plasmid-mediated tigecycline-modifying enzyme Tet(X), significantly hinders the treatment of infectious diseases in humans and animals. Livestock wastewater contributes to the transmission of these ARGs. Methods: Between June 2023 and December 2024, 140 wastewater samples from 15 swine farms in Shandong, China, were screened for tet(X)-positive strains using PCR and 16S rRNA sequencing. Raoultella ornithinolytica SD8-1 was assessed for antimicrobial susceptibility, plasmid stability, conjugation, fitness cost, and pathogenicity in a BALB/c mouse model. Furthermore, this strain was subjected to whole-genome sequencing. Results: tet(X4) was found to be located on a 78,159 bp IncFII(pCRY)-like plasmid (pSD8-1-2) in R. ornithinolytica SD8-1, exhibiting high stability (92% retention after 20 days) and conjugative transfer to E. coli C600 and blaNDM-producing E218 at frequencies of 1.6 × 10−5 and 4.3 × 10−6, respectively, with minimal fitness cost. Studies in mice showed that R. ornithinolytica SD8-1 caused severe organ damage. pSD8-1-2 led to tigecycline treatment failure, unlike the plasmid-cured strain. Database analysis identified pSD8-1-2-like plasmids or fragments were identified predominantly in Klebsiella pneumoniae, indicating a potential risk of dissemination. Conclusion: The tet(X4)-carrying plasmid pSD8-1-2 in R. ornithinolytica SD8-1 exhibits high stability and cross-species transferability, exacerbating tigecycline resistance and treatment failure. Based on the “One Health” concept, the spread of this plasmid into humans in clinical settings should be closely monitored.
Keywords: tet(X), Raoultella ornithinolytica, IncFII plasmid, Klebsiella pneumoniae, tigecycline
Received: 09 Jun 2025; Accepted: 03 Sep 2025.
Copyright: © 2025 Jia, Jin, Xi, Zhu and Cui. 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: Chaoyue Cui, Laboratory Animal Centre, Wenzhou Medical University, Wenzhou, China
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