Genome and Plasmid Analysis of blaIMP-4-Carrying Citrobacter freundii B38
Genome and Plasmid Analysis of blaIMP-4-Carrying Citrobacter freundii B38
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DOI：
10.1128/aac.00588-16
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发表时间：
2016-11-01
影响因子：
4.9
通讯作者：
Roy, Paul H.
中科院分区：
文献类型：
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作者：
Xiong, Jianhui;Deraspe, Maxime;Roy, Paul H.
使用 PacBio SMRT 技术对携带 blaIMP-4 的弗氏梭菌 B38 进行测序，结果显示该基因组包含一条 5,134,500 bp 的染色体和三个质粒：pOZ172 (127,005 bp)、pOZ181 (277,592 bp) 和 pOZ182 (18,467 bp)。与pP10164-NDM和pNDM-EcGN174一样，质粒pOZ172被鉴定为IncFIIY。它携带一个 1 类整合子，带有四个盒 (bla(IMP-4)-qacG2-aacA4-aphA15) 和一个完整的混合 tni 模块 (tniR-tniQ-tniB-tniA)。 Tn402 的 tniR（相同）与 Tn5053 的 tniQBA（99%）重组发生在 Tn402/5053 的 res 位点内。 Tn402/5053 样整合子，命名为 Tn6017，被插入 Tn1722 的 res II 位点。 pOZ181 的复制、分配和转移系统与 IncHI2 质粒（例如 R478）相似，包含 sul1 型 1 类整合子，其中盒阵列 orf-dfrA1-orfgcu37-aadA5 连接到上游 Tn1696 tnpA-tnpR 和下游 3' 保守序列 (3'-CS) 和ISCR1。在 pOZ182 上鉴定出编码 bla(TEM-1) β-内酰胺酶的 Tn2 转座子。 B38 染色体上编码的其他有趣的耐药性决定因素包括多药耐药性 (MDR) 外排泵、AmpC β-内酰胺酶以及对铜、银、砷和锌的耐药性。这是首次报道与携带 bla(IMP-4) 的 1 类整合子相关的完整 tni 模块，该模块与最近报道的其他非 sul1 整合子一起，代表了缺乏 3-CS (qacE Delta 1-sul1) 的 1 类整合子的独特进化谱系的出现。独特的盒式阵列、Tn6017 的完整 tni 模块和 pOZ172 的不相容组表明弗氏梭菌 B38 中的 blaIMP-4 进化途径不同于西太平洋地区革兰氏阴性细菌中发现的其他 blaIMP-4 基因。
Sequencing of the blaIMP-4-carrying C. freundii B38 using the PacBio SMRT technique revealed that the genome contained a chromosome of 5,134,500 bp and three plasmids, pOZ172 (127,005 bp), pOZ181 (277,592 bp), and pOZ182 (18,467 bp). Plasmid pOZ172 was identified as IncFIIY, like pP10164-NDM and pNDM-EcGN174. It carries a class 1 integron with four cassettes (bla(IMP-4)-qacG2-aacA4-aphA15) and a complete hybrid tni module (tniR-tniQ-tniB-tniA). The recombination of tniR from Tn402 (identical) with tniQBA from Tn5053 (99%) occurred within the res site of Tn402/5053. The Tn402/5053-like integron, named Tn6017, was inserted into Tn1722 at the res II site. The replication, partitioning, and transfer systems of pOZ181 were similar to those of IncHI2 plasmids (e.g., R478) and contained a sul1-type class 1 integron with the cassette array orf-dfrA1-orfgcu37-aadA5 linked to an upstream Tn1696 tnpA-tnpR and to a downstream 3' conserved sequence (3'-CS) and ISCR1. A Tn2 transposon encoding a bla(TEM-1) beta-lactamase was identified on pOZ182. Other interesting resistance determinants encoded on the B38 chromosome included multidrug resistance (MDR) efflux pumps, an AmpC beta-lactamase, and resistances to Cu, Ag, As, and Zn. This is the first report of a complete tni module linked to a bla(IMP-4)-carrying class 1 integron, which, together with other recently reported non-sul1 integrons, represents the emergence of a distinct evolutionary lineage of class 1 integrons lacking a 3-CS (qacE Delta 1-sul1). The unique cassette array, complete tni module of Tn6017, and incompatibility group of pOZ172 suggest a blaIMP- 4 evolutionary pathway in C. freundii B38 different from that for other blaIMP- 4 genes found in Gram-negative bacteria in the Western Pacific region.