Characterization of vanM carrying clinical Enterococcus isolates and diversity of the suppressed vanM gene cluster
Characterization of vanM carrying clinical Enterococcus isolates and diversity of the suppressed vanM gene cluster
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携带 vanM 的临床肠球菌分离株的特征以及受抑制的 vanM 基因簇的多样性
DOI：
10.1016/j.meegid.2018.12.015
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发表时间：
2019-03-01
影响因子：
3.2
通讯作者：
Yu, Yunsong
中科院分区：
文献类型：
--
作者：
Sun, Lingyan;Qu, Tingting;Yu, Yunsong
在这里，我们报告的流行抑制vanM基因簇作为一个水库的万古霉素耐药基因。从杭州市4家医院分离的1284株肠球菌中，筛选出55株屎肠球菌和1株粪肠球菌vanM基因型。药敏试验显示，56株vanM阳性分离株中有55株对万古霉素和替考拉宁敏感。54/56株为主要流行株系CC17型，以ST78型为主。由于IS1216E插入位点的不同，55株万古霉素敏感株vanM基因簇序列呈现多样性。vanM转座子可分为5种类型，它们都携带两个或多个IS1216E元件，导致vanR，vanS或vanX的完全或部分缺失。定量逆转录聚合酶链反应显示vanM在万古霉素敏感株中的表达水平显著低于万古霉素耐药株。考虑到vanM基因型的流行和转化为耐药表型的潜力，vanM可能在未来作为糖肽耐药的重要决定因素。应加强对万古霉素耐药肠球菌的监测，以控制万古霉素耐药的传播。
Here we report the prevalence of the suppressed vanM gene cluster as a reservoir of vancomycin resistance genes. Among 1284 clinical isolates of enterococci from four hospitals in Hangzhou, China, 55 isolates of Enterococcus faecium and one isolate of Enterococcus faecalis were screened positive for the vanM genotype. Antimicrobial susceptibility testing showed that 55 of the 56 vanM-positive isolates were susceptible to vancomycin and teicoplanin. Most of them (54/56) belonged to the main epidemic lineage CC17, mostly the ST78 type. The vanM gene clusters in the 55 vancomycin-susceptible isolates showed sequence diversity owing to different insertion locations of IS1216E. The vanM transposons could be classified into five types and they all carried two or more IS1216E elements, leading to complete or partial deletions of vanR, vanS, or vanX. Quantitative reverse transcription polymerase chain reaction showed that the expression level of vanM was significantly lower in the vancomycin-susceptible isolates than in the vancomycin-resistant isolate. Considering the prevalence of the vanM genotype and the potential for conversion to a resistant phenotype, vanM might act as an important determinant of glycopeptide resistance in the future. It is essential to strengthen the surveillance of vanM-containing enterococci to control the dissemination of vancomycin resistance.