Institut Pasteur, Unité des Bactéries Pathogènes Entériques, Centre National de Référence des Escherichia coli, Shigella et Salmonella, Paris, France.
Antimicrob Agents Chemother. 2012 Oct;56(10):5096-102. doi: 10.1128/AAC.00732-12. Epub 2012 Jul 16.
Salmonella genomic island 1 (SGI1) is a 43-kb integrative mobilizable element that harbors a great diversity of multidrug resistance gene clusters described in numerous Salmonella enterica serovars and also in Proteus mirabilis. The majority of SGI1 variants contain an In104-derivative complex class 1 integron inserted between resolvase gene res and open reading frame (ORF) S044 in SGI1. Recently, the international spread of ciprofloxacin-resistant S. enterica serovar Kentucky sequence type 198 (ST198) containing SGI1-K variants has been reported. A retrospective study was undertaken to characterize ST198 S. Kentucky strains isolated before the spread of the epidemic ST198-SGI1-K population in Africa and the Middle East. Here, we characterized 12 ST198 S. Kentucky strains isolated between 1969 and 1999, mainly from humans returning from Southeast Asia (n = 10 strains) or Israel (n = 1 strain) or from meat in Egypt (n = 1 strain). All these ST198 S. Kentucky strains did not belong to the XbaI pulsotype X1 associated with the African epidemic clone but to pulsotype X2. SGI1-J subgroup variants containing different complex integrons with a partial transposition module and inserted within ORF S023 of SGI1 were detected in six strains. The SGI1-J4 variant containing a partially deleted class 1 integron and thus showing a narrow resistance phenotype to sulfonamides was identified in two epidemiologically unrelated strains from Indonesia. The four remaining strains harbored a novel SGI1-J variant, named SGI1-J6, which contained aadA2, floR2, tetR(G)-tetA(G), and sul1 resistance genes within its complex integron. Moreover, in all these S. Kentucky isolates, a novel insertion sequence related to the IS630 family and named ISSen5 was found inserted upstream of the SGI1 complex integron in ORF S023. Thus, two subpopulations of S. Kentucky ST198 independently and exclusively acquired the SGI1 during the 1980s and 1990s. Unlike the ST198-X1 African epidemic subpopulation, the ST198-X2 subpopulation mainly from Asia harbors variants of the SGI1-J subgroup that are encountered mainly in the Far East, as previously described for S. enterica serovars Emek and Virchow.
沙门氏菌基因组岛 1（SGI1）是一个 43kb 的整合可移动元件，它含有大量的多药耐药基因簇，这些基因簇在许多沙门氏菌血清型和奇异变形杆菌中都有描述。大多数 SGI1 变体包含一个 In104 衍生的复杂 1 类整合子，插入 SGI1 中的 resolvase 基因 res 和开放阅读框（ORF）S044 之间。最近，含有 SGI1-K 变体的环丙沙星耐药肠炎沙门氏菌血清型 198（ST198）在非洲和中东的流行 ST198-SGI1-K 人群传播之前，已经报道了其国际传播。本回顾性研究旨在描述在非洲和中东流行的 ST198-SGI1-K 人群传播之前分离的 ST198 肯塔基州血清型沙门氏菌菌株。在这里，我们描述了 1969 年至 1999 年间分离的 12 株 ST198 肯塔基州血清型沙门氏菌菌株，这些菌株主要来自从东南亚返回的人（10 株来自人类）或以色列（1 株来自人类）或来自埃及的肉类（1 株来自肉类）。所有这些 ST198 肯塔基州血清型沙门氏菌菌株均不属于与非洲流行克隆相关的 XbaI 脉冲型 X1，而是属于脉冲型 X2。在 6 株菌株中检测到包含部分转位模块的不同复杂整合子的 SGI1-J 亚组变体，并插入 SGI1 的 ORF S023 内。在来自印度尼西亚的两个流行病学上无关的菌株中，鉴定出了含有部分缺失的 1 类整合子的 SGI1-J4 变体，该变体对磺胺类药物表现出狭窄的耐药表型。其余 4 株菌株携带一种新型的 SGI1-J 变体，命名为 SGI1-J6，该变体在其复杂整合子内含有 aadA2、floR2、tetR(G)-tetA(G)和 sul1 耐药基因。此外，在所有这些肯塔基州分离株中，发现了一种与 IS630 家族相关的新型插入序列，命名为 ISSen5，并插入 SGI1 复杂整合子上游的 ORF S023 中。因此，在 20 世纪 80 年代和 90 年代，两个独立且专有的 S. 肯塔基州 ST198 亚群独立获得了 SGI1。与非洲流行的 ST198-X1 亚群不同，主要来自亚洲的 ST198-X2 亚群携带的 SGI1-J 亚群变体主要在远东地区发现，如以前描述的肠炎沙门氏菌血清型 Emek 和 Virchow 一样。
