Department of Clinical Laboratory Center, Beijing Children's Hospital, National Center for Children's Health, Capital Medical University, Beijing, China.
Taizhou Hospital of Zhejiang Province Affiliated to Wenzhou Medical University, Linhai, China.
J Glob Antimicrob Resist. 2024 Jun;37:157-164. doi: 10.1016/j.jgar.2024.03.006. Epub 2024 Mar 28.
Herein, we detected one multidrug-resistant Aeromonas hydrophila strain K522 co-carrying two bla genes together with a novel chromosomal integrative and mobilizable element (IME) Tn7548 from China. To reveal the genetic characteristics of the novel reservoir of bla and IME in Aeromonas, a detailed genomic characterization of K522 was performed, and a phylogenetic analysis of Tn7412-related IMEs was carried out.
Carbapenemases were detected by using the immunocolloidal gold technique and antimicrobial susceptibility was tested by using VITEK 2. The whole-genome sequences of K522 were analysed using phylogenetics, detailed dissection, and comparison.
Strain K522 carried a Tn7412-related chromosomal IME Tn7548 and three resistance plasmids pK522-A-KPC, pK522-B-KPC, and pK522-MOX. A phylogenetic tree of 82 Tn7412-related IMEs was constructed, and five families of IMEs were divided. These IMEs shared four key backbone genes: int, repC, and hipAB, and carried various profiles of antimicrobial resistance genes (ARGs). pK522-A-KPC and pK522-B-KPC carried bla and belonged to IncG and unclassified type plasmid, respectively. The bla regions of these two plasmids were the truncated version derived from Tn6296, resulting in the carbapenem resistance of K522.
We first reported A. hydrophila harbouring a novel Tn7412-related IME Tn7548 together with two bla carrying plasmids and a MDR plasmid. Three of these four mobile genetic elements (MGEs) discovered in A. hydrophila K522 were novel. The emergence of novel MGEs carrying ARGs indicated the rapid evolution of the resistance gene vectors in A. hydrophila under selection pressure and would contribute to the further dissemination of various ARGs in Aeromonas.
本文从中国分离到一株同时携带两个 bla 基因和一个新型染色体整合和可移动元件（IME）Tn7548 的多药耐药气单胞菌 K522 菌株。为了揭示气单胞菌 bla 和 IME 新型储库的遗传特征，对 K522 进行了详细的基因组特征分析，并对 Tn7412 相关 IME 进行了系统发育分析。
采用免疫胶体金技术检测碳青霉烯酶，采用 VITEK 2 检测抗菌药物敏感性。利用系统发育、详细剖析和比较分析 K522 的全基因组序列。
K522 株携带 Tn7412 相关染色体 IME Tn7548 和三个耐药质粒 pK522-A-KPC、pK522-B-KPC 和 pK522-MOX。构建了 82 个 Tn7412 相关 IME 的系统发育树，分为五个 IME 家族。这些 IME 共享四个关键核心基因：int、repC 和 hipAB，并携带各种抗菌药物耐药基因（ARGs）。pK522-A-KPC 和 pK522-B-KPC 携带 bla 基因，分别属于 IncG 和未分类型质粒。这两个质粒的 bla 区是来自 Tn6296 的截断版本，导致 K522 对碳青霉烯类药物的耐药性。
我们首次报道了一株携带新型 Tn7412 相关 IME Tn7548 的气单胞菌，同时还携带两个 bla 基因和一个 MDR 质粒。在气单胞菌 K522 中发现的这四个移动遗传元件（MGEs）中的三个是新型的。新型 MGEs 携带 ARGs 表明，在选择压力下，气单胞菌中的耐药基因载体快速进化，并有助于 Aeromonas 中各种 ARGs 的进一步传播。
