Molecular characterization of vancomycin-resistant Enterococcus faecium isolates from mainland China
Molecular characterization of vancomycin-resistant Enterococcus faecium isolates from mainland China
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DOI：
10.1128/jcm.00457-07
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发表时间：
2007-09-01
影响因子：
9.4
通讯作者：
Ike, Yasuyoshi
中科院分区：
文献类型：
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作者：
Zheng, Bo;Tomita, Haruyoshi;Ike, Yasuyoshi
我国对万古霉素耐药肠球菌知之甚少。从2001年至2005年，从中国五家医院获得了13株经脉冲场凝胶电泳证实的异质性VanA型万古霉素耐药屎肠球菌（VRF）分离株。通过多位点序列分型将分离株分为9种不同的序列类型（ST），包括5种新的ST（ST 18、ST 25、ST 78、ST 203、ST 320、ST 321、ST 322、ST 323和ST 335）。每个分离株中的万古霉素耐药性由接合质粒编码;其中两个质粒pZB 18（67 kbp）和pZB 22（200.kbp）具有高度接合性，并且能够在肉汤交配中分别以约10（-4）和10（-7）/供体细胞的高频率转移。在这些分离物中鉴定的质粒均不携带traA，traA通常在大肠杆菌的pMG 1样高接合性质粒中是保守的。pZB 18和pZB 22是肠球菌中一种新型的高接合性质粒。接合质粒上的13个Tn 1546样元件编码VanA型VRE，分为6种类型（I至VI型），其中大多数含有IS 1216 V和IS 1542插入。携带11型元件的菌株占优势。这6个基因型元件与从中国鸡肉中分离的VanA型粪肠球菌不同。结果表明，VRE在这些地区的传播是通过接合质粒获得Tn 1546样元件并在E.粪菌菌株
Little is known about vancomycin-resistant enterococei in China. Thirteen pulsed-field gel electrophoresis-confirmed heterogeneous VanA-type vancomycin-resistant Enterococcus faecium (VRF) isolates were obtained from five Chinese hospitals from 2.001 to 2005. The isolates were typed by multilocus sequence typing into nine different sequence types (STs), including five new STs (ST18, ST25, ST78, ST203, ST320, ST321, ST322, ST323, and ST335). Vancomycin resistance in each isolate was encoded on conjugative plasmids; two of the plasmids, pZB18 (67 kbp) and pZB22 (200.kbp), were highly conjugative and were able to transfer at high frequencies of around 10(-4) and 10(-7) per donor cell in broth mating, respectively. None of the plasmids identified in these isolates carried traA, which is usually conserved in the pMG1-like highly conjugative plasmid for E. faecium, implying that pZB18 and pZB22 were novel types of a highly conjugative plasmid in enterococci. Thirteen Tn1546-like elements encoding VanA-type VRE on the conjugative plasmids were classified into six types (types I to VI), and most of them contained both IS1216V and IS1542 insertions. The isolates carrying the type 11 element were predominant. The six type elements were different from that of a VanA-type Enterococcus faecalis strain isolated from Chinese chicken meat. The results suggested that the disseminations of VRE in these areas were by Tn1546-like elements being acquired by the conjugative plasmids and transferred among E. faecium strains.