Novel arrangement of the blaCTX-M-55 gene in an Escherichia coli isolate coproducing 16S rRNA methylase
Novel arrangement of the blaCTX-M-55 gene in an Escherichia coli isolate coproducing 16S rRNA methylase
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DOI：
10.1002/jobm.201200318
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发表时间：
2013-11-01
影响因子：
3.1
通讯作者：
Hu, Gong-Zheng
中科院分区：
文献类型：
--
作者：
Pan, Yu-Shan;Liu, Jian-Hua;Hu, Gong-Zheng
从我国某鸡群中分离到一株多重耐药大肠杆菌C21。PCR检测结果显示，该株细胞具有bla（TEM-1）、bla（CTX-M-55）和rmtB基因。对该菌株进行了系统发育分类、接合试验、质粒分析、PCR复制子分型和多位点序列分型。利用PCR定位技术对bla（CTX-M-55）的遗传环境进行了研究。该菌株属于放线菌A群，编号ST 156。发现bla（CTX-M-55）和rmtB基因存在于分别属于IncI 1和IncN家族的不同质粒中。这些耐药质粒可以单独或一起转移到受体菌株中。初步鉴定了ISEcp 1-IS 1294-ISEcp 1-bla（CTX-M-55）-ORF 477的一种新排列，其中ISEcp 1元件被另一个IS 1294元件破坏。本研究中发现的接合转移和IS元件可导致bla（CTX-M-55）和rmtB在肠杆菌科菌株中快速传播，对畜牧业和公共卫生构成威胁。
A multi-drug resistant Escherichia coli C21 was isolated from a chicken in China. It was shown to be positive for the presence of the bla(TEM-1), bla(CTX-M-55) and rmtB genes by PCR. This strain was examined by phylogenetic grouping, conjugation experiments, plasmid analysis, PCR-based replicon typing and multi-locus sequence typed (MLST). The genetic environment of bla(CTX-M-55) was investigated by PCR mapping. The strain belonged to phylogroup A, ST156. The bla(CTX-M-55) and rmtB genes were found to be present in separate plasmids that belonged to the IncI1 and IncN families, respectively. These antibiotic-resistant plasmids could be transferred to the recipient strain alone or together. A new arrangement of ISEcp1-IS1294-ISEcp1-bla(CTX-M-55)-ORF477, in which the ISEcp1 element was disrupted by another IS1294 element, was identified initially. Conjugative transfer and IS elements found in this study could lead to the rapid dissemination of bla(CTX-M-55) and rmtB among strains of Enterobacteriaceae, which could pose a threat to animal husbandry and public health.