Detection of chromosomal blaCTX-M-15 in Escherichia coli O25b-B2-ST131 isolates from the Kinki region of Japan
Detection of chromosomal blaCTX-M-15 in Escherichia coli O25b-B2-ST131 isolates from the Kinki region of Japan
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DOI：
10.1016/j.ijantimicag.2013.08.005
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发表时间：
2013-12-01
影响因子：
10.8
通讯作者：
Yamamoto, Yoshimasa
中科院分区：
文献类型：
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作者：
Hirai, Itaru;Fukui, Naoki;Yamamoto, Yoshimasa
携带 bla(CTX) (M) (15) 的大肠杆菌 O25b-B2-ST131 分离株分布于世界各地。 bla(CTX) (M) (15) 转座单位经常在质粒上发现，并且其遗传背景已被检查；然而，人们对染色体上 bla(CTX-M-15) 转座单元的频率和背景知之甚少。本研究旨在确定大肠杆菌 O25b-B2-ST131 分离株中 bla(CTX-M-15) 转座单元的染色体位置，并分析 bla(CTX-M-15) 转座单元周围区域的分子结构。对从日本近畿地区的大学医院患者和疗养院居民中分离出的 22 株含有 bla(CTX-M-15) 的大肠杆菌 O25b-B2-ST131 菌株进行了检查。进行针对 bla(CTX-M-15) 的反向 PCR (iPCR)，对 bla(CTX-M-15) 转座单元周围区域的分子结构进行分类。考虑到 iPCR 结果，将分离株分为九个类型（A-I 型）； A 型是最常见的类型（13/22 分离株）。 iPCR扩增DNA片段序列显示bla(CTX-M-15)转座单元由ISEcp1、bla(CTX-M-15)和orf477 Delta组成。对获得的序列进行同源性搜索表明，bla(CTX-M-15)转座单元被插入到九个分类类型中的八个的不同染色体区域中。尽管 22 株大肠杆菌分离株中有 21 株具有染色体定位的 bla(CTX-M-15) 转座单位，但脉冲场凝胶电泳 (PFGE) 分析显示克隆扩散并不明显。总而言之，这些数据表明某些携带染色体 bla(CTX-M-15) 的大肠杆菌 O25b-B2-ST131 菌株已在日本近畿地区出现并传播。 (C) 2013 Elsevier B.V. 和国际化疗协会。版权所有。
Escherichia coli O25b-B2-ST131 isolates harbouring bla(CTX) (M) (15) are distributed worldwide. The bla(CTX) (M) (15) transposition unit has often been found on plasmids and the genetic contexts have been examined; however, less is known about the frequency and contexts of the bla(CTX-M-15) transposition unit on the chromosome. This study was performed to determine the chromosomal location of the bla(CTX-M-15) transposition unit and to analyse the molecular structure of the region surrounding the bla(CTX-M-15) transposition unit in E. coli O25b-B2-ST131 isolates. Twenty-two E. coli O25b-B2-ST131 strains harbouring bla(CTX-M-15) that had been isolated from university hospital patients and nursing home residents in the Kinki region of Japan were examined. Inverse PCR (iPCR) targeting bla(CTX-M-15) was performed to classify the molecular structure of the region surrounding the bla(CTX-M-15) transposition unit. The isolates were classified into nine types (types A-I) considering the iPCR results; type A was the most prevalent type (13/22 isolates). Sequences of the iPCR-amplified DNA fragments showed that the bla(CTX-M-15) transposition unit consisted of ISEcp1, bla(CTX-M-15) and orf477 Delta. A homology search of the obtained sequences showed that the bla(CTX-M-15) transposition unit was inserted into different chromosomal regions in eight of the nine classified types. Although 21 of the 22 E. coli isolates possessed chromosomally located bla(CTX-M-15) transposition units, clonal spread was not evident on pulsed-field gel electrophoresis (PFGE) analysis. Taken together, these data indicate that certain E. coli O25b-B2-ST131 strains harbouring chromosomal bla(CTX-M-15) have emerged and spread in the Kinki region of Japan. (C) 2013 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.