Department of Laboratory Medicine, The General Hospital of Chinese People’s Armed Police Forces, Beijing, China.
Antimicrob Agents Chemother. 2012 Apr;56(4):1698-702. doi: 10.1128/AAC.06199-11. Epub 2012 Jan 30.
The spread of the bla(NDM-1) gene is gaining worldwide attentions. This gene is usually carried by large plasmids and has been discovered in diverse bacteria since it was originally found in Klebsiella pneumoniae. Here we report the complete sequences of a bla(NDM-1)-bearing plasmid, pNDM-BJ01, and its variant, pNDM-BJ02, isolated from clinical Acinetobacter lwoffii strains. The plasmid pNDM-BJ01 is 47.3 kb in size and cannot be classified into any known plasmid incompatibility group, thus representing a novel plasmid with an unknown maintenance mechanism. This plasmid contains both a bla(NDM-1) gene and a type IV secretion system (T4SS) gene cluster. The T4SS is assigned to the P-type T4SS group, which usually encode a short, rigid pilus, and the bla(NDM-1) gene is located within a composite transposon flanked by two insertion elements of ISAba125. Plasmid pNDM-BJ02 is nearly identical to pNDM-BJ01 except that one copy of the ISAba125 element is missing, and it is therefore regarded as a variant of pNDM-BJ01. Sequence alignment indicated that this bla(NDM-1)-containing composite transposon, which can also be captured by other mobile elements, was probably a product of multiple recombination events and can move as a whole by transposition.
bla(NDM-1)基因的传播引起了全球关注。该基因通常由大型质粒携带，最初在肺炎克雷伯菌中发现，现已在多种细菌中发现。在这里，我们报告了两株临床分离的鲍曼不动杆菌携带 bla(NDM-1)的质粒 pNDM-BJ01 和 pNDM-BJ02 的完整序列。质粒 pNDM-BJ01 大小为 47.3 kb，不能归入任何已知的质粒不相容群，因此代表了一种具有未知维持机制的新型质粒。该质粒既包含 bla(NDM-1)基因，又包含一个 IV 型分泌系统（T4SS）基因簇。T4SS 被分配到 P 型 T4SS 组，该组通常编码短而刚性的菌毛，bla(NDM-1)基因位于由两个插入元件 ISAba125 侧翼的复合转座子内。质粒 pNDM-BJ02 与 pNDM-BJ01 几乎完全相同，只是缺少一个 ISAba125 元件，因此被认为是 pNDM-BJ01 的一个变体。序列比对表明，这个携带 bla(NDM-1)的复合转座子，也可以被其他移动元件捕获，可能是多次重组事件的产物，并可以通过转座整体移动。
