ORIGINAL RESEARCH article
Front. Cell. Infect. Microbiol.
Sec. Antibiotic Resistance and New Antimicrobial drugs
Prevalent and diverse new plasmid-encoded heavy metal and antimicrobial resistance in Klebsiella strains isolated from hospital wastewater
Provisionally accepted
Grace Pascale Engobo
Wenya Su
Shengyao WangZhen Yan
Youming ZhangMengge ZhangXueyun Geng
Hai Xu
Ling Li*
Mingyu Wang*- Shandong University, Jinan, China
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The rise of antibiotic-resistant Klebsiella pneumoniae poses a significant global health threat. Plasmids, as mobile genetic elements, play a critical role in bacterial adaptation by facilitating the spread of resistance genes. To analyze plasmid-mediated antibiotic and heavy metal resistance in clinical Klebsiella strains, 33 Klebsiella strains isolated from wastewater were subjected to third-generation nanopore sequencing to obtain high-quality whole-genome assemblies. The presence and diversity of plasmids associated with antibiotic and heavy metal resistance were analyzed, and phenotypic assays were conducted to confirm metal resistance. A total of 81 plasmids were identified across 24 strains, including 28 (34.6%) novel plasmids. Among them, 22 plasmids carried antibiotic resistance genes (ARGs), with 12 containing integrons, four of which were complex Class I integrons and two unconventional integrons. Notably, a novel conjugative plasmid, pKP228-1, was discovered carrying a complex Class I integron with a unique gene cassette array encoding 12 ARGs, and harboring blaNDM-1 in the adjacent ISCR1-associated region. Another plasmid, pKP174-2, harbored mcr-8.1 and tporJ1-tmexCD1. Additionally, 24 plasmids encoded resistance to eight heavy metals/metalloids, and 12 plasmids co-harbored both ARGs and metal resistance genes, indicating potential co-selection mechanisms. This study highlights the extensive diversity and novel structures of plasmids carrying both antibiotic and heavy metal resistance in clinical Klebsiella isolates. The observed co-occurrence of the two resistance types highlights the need for comprehensive genomic surveillance to monitor the spread of multi-resistance determinants.
Keywords: Klebsiella, Plasmid, Hospital wastewater, metal resistance, antimicrobial resistance, integron
Received: 25 Jun 2025; Accepted: 07 Nov 2025.
Copyright: © 2025 Engobo, Su, Wang, Yan, Zhang, Zhang, Geng, Xu, Li and Wang. 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:
Ling Li, lingli@sdu.edu.cn
Mingyu Wang, wangmingyu@sdu.edu.cn
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