Department of Microbiology and Infectious Diseases, Toho University Graduate School of Medicine, Tokyo, Japan.
Department of Microbiology, Tokyo Metropolitan Institute of Public Health, Tokyo, Japan.
Microbiol Spectr. 2022 Aug 31;10(4):e0144922. doi: 10.1128/spectrum.01449-22. Epub 2022 Jul 13.
Dissemination of , which is carried on the IncX3 plasmid, among has been reported worldwide. In particular, -carrying IncX3 plasmids can spread among several hosts, facilitating their dissemination. Other variants, such as -, -, -, -, and -carrying IncX3 plasmids, have also been reported. Here, we characterized, using whole-genome sequencing (WGS), a -carrying IncX3 plasmid harbored by Escherichia coli strain TA8571, which was isolated from a urine specimen of a hospital inpatient in Tokyo, Japan. The differed in sequence from (C > T at site 698, resulting in an Ala233Val substitution). This -carrying IncX3 plasmid (pTMTA8571-1) is 46,161 bp in length and transferred via conjugation. Transconjugants showed high resistance to β-lactam antimicrobials (except for aztreonam). Because pTMTA8571-1, which carries the Tnrelated region containing and conjugative transfer genes, was similar to the previously reported IncX3 plasmids, we performed phylogenetic analysis based on the sequence of 34 shared genes in 142 -carrying IncX3 plasmids (22,846/46,923 bp). Comparative analysis of the shared genes revealed short branches on the phylogenetic tree (average of 1.08 nucleotide substitutions per shared genes), but each variant was divided into separate groups, and the structure of the tree correlated with the flowchart of nucleotide substitutions. The -carrying IncX3 plasmids may thereby have evolved from the same ancestral plasmid with subsequent mutation of the . Therefore, pTMTA8571-1 likely emerged from a -carrying IncX3 plasmid. This study suggested that the spread of -carrying IncX3 plasmids may be a hotbed for the emergence of novel variants of . -carrying IncX3 plasmids have been reported worldwide. Harbored variants were mainly , but there were also rare variants like , , , , and , including detected in this study. For these plasmids, previous reports analyzed whole genomes or parts of sequences among a small number of samples, whereas, in this study, we performed an analysis of 142 -carrying IncX3 plasmids detected around the world. The results showed that regardless of the variants, -carrying IncX3 plasmids harbored highly similar shared genes. Because these plasmids already spread worldwide may be a hotbed for the emergence of rare or novel variants of , increased attention should be paid to -carrying IncX3 plasmids in the future.
在全球范围内，已经报道了在 中传播的 ，其中包括在 中传播的 。特别是，携带 IncX3 质粒的 可以在多个宿主之间传播，从而促进了它们的传播。其他变体，如 、 、 、 和 携带的 IncX3 质粒，也已被报道。在这里，我们使用全基因组测序 (WGS) 对从日本东京一家医院住院患者尿液样本中分离到的携带 的 大肠杆菌菌株 TA8571 进行了表征。 与 （698 位的 C>T，导致丙氨酸 233 到缬氨酸的取代）在序列上有所不同。这种携带 IncX3 质粒 (pTMTA8571-1) 长 46161bp，通过接合进行转移。转导子对β-内酰胺类抗生素（除氨曲南外）表现出高抗性。由于 pTMTA8571-1 携带包含 和可接合转移基因的 Tn 相关区域，与先前报道的 IncX3 质粒相似，因此我们基于 142 个携带 IncX3 的质粒中 34 个共享基因的序列进行了系统发育分析（22,846/46,923bp）。共享基因的比较分析表明系统发育树上的分支较短（每个共享基因平均有 1.08 个核苷酸取代），但每个 变体都被分为单独的组，并且树的结构与 核苷酸取代的流程图相关。因此，携带 IncX3 的质粒可能是从同一祖先质粒进化而来，随后发生了 的突变。因此，pTMTA8571-1 可能源自携带 IncX3 的质粒。本研究表明，携带 IncX3 的质粒的传播可能是 的新型变体出现的温床。全球范围内已报道 携带 IncX3 质粒。携带的变体主要是 ，但也有罕见的变体，如 、 、 、 和 ，包括本研究中检测到的 。对于这些质粒，以前的报告分析了少数样本中的全基因组或部分序列，而在这项研究中，我们对全球范围内检测到的 142 个携带 IncX3 的质粒进行了分析。结果表明，无论 变体如何，携带 IncX3 的质粒都含有高度相似的共享基因。由于这些质粒已经在全球范围内传播，可能是罕见或新型 变体出现的温床，因此未来应更加关注携带 IncX3 的质粒。
