Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China.
State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
Sci Rep. 2017 Aug 24;7(1):9405. doi: 10.1038/s41598-017-09624-0.
Two novel New Delhi metallo-β-lactamase-1 (NDM-1)-positive plasmids containing a complete composite transposon, Tn125, from two respective Acinetobacter towneri isolates were characterized. Plasmid pNDM-GJ01 (30,293 bp) isolated from A. towneri G165 did not show homology to any known plasmid structure, except for the transposon Tn125 containing bla . A novel repB gene and two XRE-type transcriptional regulators were found in pNDM-GJ01. Plasmid pNDM-GJ02 (62,011 bp) isolated from A. towneri G295 showed the highest homology to pBJAB0715 (41% coverage, 99% nucleotide identity). In addition to the bla -harbouring transposon Tn125, pNDM-GJ02 also had an IS26-composite transposon, which contains ISCR1 and two class 1 integrons carrying different cassette arrays. Both clinical isolates were highly resistant to β-lactams and susceptible to tigecycline and colistin. Ten other resistance genes were detected in G295, and one other resistance gene was detected in G165. No transconjugant was obtained from any of the donors by broth and filter mating. The emergence of these two novel plasmids carrying NDM-1 in Acinetobacter spp., pNDM-GJ01 and pNDM-GJ02, suggests Tn125 mobile integration.
两个新型新德里金属β-内酰胺酶 1（NDM-1）阳性质粒，均含有来自两个各自的不动杆菌分离株的完整复合转座子 Tn125，其特征如下。质粒 pNDM-GJ01（30293bp）从不动杆菌 G165 中分离，与任何已知质粒结构均无同源性，除了转座子 Tn125 含有 bla 。在 pNDM-GJ01 中发现了一个新型 repB 基因和两个 XRE 型转录调节因子。质粒 pNDM-GJ02（62011bp）从不动杆菌 G295 中分离，与 pBJAB0715（41%覆盖度，99%核苷酸同一性）显示出最高同源性。除了 bla 基因携带的转座子 Tn125 外，pNDM-GJ02 还含有一个 IS26 复合转座子，其中包含 ISCR1 和两个携带不同盒式数组的 I 类整合子。两个临床分离株对β-内酰胺类高度耐药，对替加环素和粘菌素敏感。在 G295 中检测到 10 个其他耐药基因，在 G165 中检测到 1 个其他耐药基因。通过肉汤和滤膜交配，没有从任何供体中获得转导体。这两个新型携带 NDM-1 的质粒在不动杆菌属中的出现，pNDM-GJ01 和 pNDM-GJ02，提示 Tn125 移动整合。
