Wang Xue-Chun, Lei Chang-Wei, Kang Zhuang-Zhuang, Zhang Yu, Wang Hong-Ning
Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, China.
Front Microbiol. 2019 Sep 24;10:2245. doi: 10.3389/fmicb.2019.02245. eCollection 2019.
genomic island 1 (SGI1) is an integrative mobilizable element integrated into the chromosome of bacteria, which plays an important role in the dissemination of antimicrobial resistance genes. Lots of SGI1 variants are found mainly in and . In this study, a total of 157 and 132 strains were collected from food-producing animals in Sichuan Province of China between December 2016 and November 2017. Detection of the SGI1 integrase gene showed that three and five strains were positive for SGI1, which displayed different multidrug resistance profiles. Five different SGI1 variants, including two novel variants (SGI1-PmBC1123 and SGI1-PmSC1111), were characterized by whole genome sequencing and PCR linkage. In two novel SGI1 variants, IS-mediated rearrangements resulted in large sequence inversions of the MDR regions extending outside the SGI1 backbone. The -type III class 1 integron (5'CS-------IS440-) and gene cassettes ' -- are found in SGI1-PmSC1111. Mobilization experiments indicated that three known variants were conjugally mobilized in to with the help of a conjugative IncC plasmid. However, the two novel variants seemed to lose the mobilization, which might result from the sequence inversion of partial SGI1 backbone. The identification of the two novel SGI1 variants in this study suggested that IS-mediated rearrangements promote the diversity of SGI1.
基因组岛1（SGI1）是一种整合到细菌染色体中的可整合移动元件，在抗菌药物耐药基因的传播中起重要作用。大量SGI1变体主要在[具体位置1]和[具体位置2]中被发现。在本研究中，2016年12月至2017年11月期间，从中国四川省的食用动物中总共收集了157株[细菌类型1]和132株[细菌类型2]菌株。SGI1整合酶基因检测显示，3株[细菌类型1]和5株[细菌类型2]菌株的SGI1呈阳性，它们表现出不同的多重耐药谱。通过全基因组测序和PCR连锁分析鉴定了5种不同的SGI1变体，包括2种新变体（SGI1-PmBC1123和SGI1-PmSC1111）。在2种新的SGI1变体中，IS介导的重排导致MDR区域的大序列倒位延伸到SGI1主干之外。在SGI1-PmSC1111中发现了I类III型整合子（5'CS-------IS440-）和基因盒'[具体基因盒内容] --。迁移实验表明，在接合型IncC质粒的帮助下，3种已知变体在[受体菌类型]中以[X]至[Y]的频率进行接合迁移。然而，这2种新变体似乎失去了迁移能力，这可能是由于部分SGI1主干的序列倒位所致。本研究中2种新SGI1变体的鉴定表明，IS介导的重排促进了SGI1的多样性。
