Sun Huarun, Zhang Junkai, Miao Qingqing, Zhai Yajun, Pan Yushan, Yuan Li, Yan Fengbin, Wu Hua, Hu Gongzheng
Department of Pharmacology and Toxicology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, China.
Front Vet Sci. 2022 Aug 19;9:986824. doi: 10.3389/fvets.2022.986824. eCollection 2022.
Integrative conjugative elements (ICEs) are important carriers for disseminating resistance genes. We have previously reported a novel element ICE carrying seven antibiotic resistance genes, which could be self-transmissible relying on the novel T4SS. To identify novel ICE variants from 211 strains and novel T4SS encoded in ICE, and to explore the relationships in these ICEs, four complete sequences of ICEs were identified by WGS analysis and antimicrobial susceptibility testing was determined by broth microdilution. In addition, a comparative analysis of these ICEs was conducted with bioinformatic tools, and the transfer abilities of these ICEs were confirmed by conjugation. Four ICE variants ICE, ICE, ICE, and ICE with different resistance gene profiles were characterized, and their hosts showed different resistance spectrums. All ICEs shared the same backbone and were inserted into the tRNA site, and all resistance regions were inserted into the same target site between the accessory and integration regions. This study analyzed complete sequences of ICEs from the ICE family and identified novel T4SS and insertion element IS. Diverse resistance genes extensively exist in these ICEs, serving as a reservoir for resistance genes and facilitating their dissemination.
整合性接合元件（ICEs）是传播耐药基因的重要载体。我们之前报道过一种携带7个抗生素耐药基因的新型元件ICE，它可依靠新型IV型分泌系统（T4SS）进行自我传递。为了从211株菌株中鉴定新型ICE变体以及ICE中编码的新型T4SS，并探究这些ICEs之间的关系，通过全基因组测序（WGS）分析鉴定出4个ICE的完整序列，并用肉汤微量稀释法测定抗菌药敏性。此外，利用生物信息学工具对这些ICEs进行了比较分析，通过接合试验证实了这些ICEs的转移能力。鉴定出了4种具有不同耐药基因谱的ICE变体ICE、ICE、ICE和ICE，它们的宿主表现出不同的耐药谱。所有ICEs都具有相同的主干结构并插入到tRNA位点，所有耐药区域都插入到辅助区域和整合区域之间的同一靶点。本研究分析了ICE家族中ICEs的完整序列，鉴定出新型T4SS和插入元件IS。这些ICEs中广泛存在多种耐药基因，它们是耐药基因的储存库并促进其传播。
