Laboratory of Bacteriology, Dijon University Hospital, Plateau technique de Biologie, BP 37013, 21070 Dijon cedex, France.
UMR 6249 CNRS Chrono-environnement, Université de Bourgogne Franche-Comté, 25000 Besançon, France.
J Antimicrob Chemother. 2018 Jul 1;73(7):1804-1807. doi: 10.1093/jac/dky108.
To characterize the structure of Salmonella genomic islands 1 (SGI1s) from two clinical Proteus mirabilis isolates: one producing an ESBL and the other a penicillinase.
WGS completed by PCR and Sanger sequencing was performed to determine sequences of SGI1s from Pm2CHAMA and Pm37THOMI strains.
Two new variants of SGI1 named SGI1-Pm2CHAMA (53.6 kb) and SGI1-K7 (55.1 kb) were identified. The backbone of SGI1-Pm2CHAMA shared 99.9% identity with that of SGI1. Its MDR region (26.3 kb) harboured two class 1 integrons (an In2-type integron and an In4-type integron) containing in particular a qacH cassette (encoding a quaternary ammonium compound efflux pump). These two integrons framed a complex region (harbouring among others blaCARB-4) resulting from transposon insertions mediated by IS26 and successive transposition events of ISs (ISAba14 isoform and the new ISPmi2). The second variant (SGI1-K7) had the same backbone as SGI1-K. Its MDR region (29.7 kb) was derived from that of SGI1-K and was generated by three events. The two main events were mediated by IS26: inversion of a large portion of the MDR region of SGI1-K and insertion of a structure previously reported on plasmids carried by prevalent and successful MDR clones of Enterobacteriaceae. This last event led to the insertion of the blaCTX-M-15 gene into SGI1-K7.
This study confirmed the great plasticity of the MDR region of SGI1 and its potential key role for the dissemination of clinically significant antibiotic resistance among Enterobacteriaceae.
对来自临床奇异变形杆菌 2 株（产生 ESBL 和青霉素酶）的沙门氏菌基因组岛 1（SGI1）进行结构特征分析。
通过 PCR 和 Sanger 测序完成 WGS，以确定 Pm2CHAMA 和 Pm37THOMI 菌株 SGI1 的序列。
鉴定出两种新的 SGI1 变体，分别命名为 SGI1-Pm2CHAMA（53.6kb）和 SGI1-K7（55.1kb）。SGI1-Pm2CHAMA 的骨架与 SGI1 高度同源（99.9%）。其 MDR 区（26.3kb）含有 2 个 1 类整合子（In2 型整合子和 In4 型整合子），特别是包含 qacH 盒（编码季铵化合物外排泵）。这两个整合子框定了一个复杂的区域（还包含 blaCARB-4 等），是由 IS26 介导的转座子插入和 IS （ISAba14 同种型和新的 ISPmi2）的连续转位事件引起的。第二个变体（SGI1-K7）与 SGI1-K 具有相同的骨架。其 MDR 区（29.7kb）源自 SGI1-K，由 3 个事件产生。两个主要事件由 IS26 介导：SGI1-K 的 MDR 区的大部分发生反转，以及先前报道的结构插入到肠杆菌科中流行和成功的 MDR 克隆所携带的质粒中。这最后一个事件导致 blaCTX-M-15 基因插入到 SGI1-K7 中。
本研究证实了 SGI1 的 MDR 区具有很强的可塑性，它可能是肠杆菌科中临床重要的抗生素耐药性传播的关键因素。
