Multilocus sequence typing of IncI1 plasmids carrying extended-spectrum β-lactamases in Escherichia coli and Salmonella of human and animal origin
Multilocus sequence typing of IncI1 plasmids carrying extended-spectrum β-lactamases in Escherichia coli and Salmonella of human and animal origin
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DOI：
10.1093/jac/dkn131
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发表时间：
2008-06-01
影响因子：
5.2
通讯作者：
Carattoli, Alessandra
中科院分区：
文献类型：
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作者：
Garcia-Fernandez, Aurora;Chiaretto, Giuseppina;Carattoli, Alessandra
目的：属于不相容组i_1 （IncI1）的质粒在肠杆菌科广泛存在，其特征是存在编码IV型菌毛的基因簇，有助于志贺毒素大肠杆菌的毒力。最近，在动物源性大肠杆菌和沙门氏菌菌株中发现了IncI1质粒，该质粒负责β -内酰胺酶基因的传播。质粒多位点序列分型（pMLST）是根据天然存在的ince1质粒的等位基因分类在同质群体中进行识别的一种方法。方法：在现有的IncI1质粒完整DNA序列上选择多个靶基因，构建pMLST。本研究共纳入16个质粒，均通过pcr复制子分型方法归入IncI1组。采用限制性内切片段长度多态性（RFLP）和pMLST分型，分析了β -内酰胺酶基因。结果：从不同国家动物和人分离的大肠杆菌和沙门氏菌中鉴定出16个质粒携带bla（CMY-2）、bla（CTX-M-15）、bla（CTX-M-1）、bla（CTX-M-14）、bla（TEM-52）、bla（SHV-12）和bla(TEM-1) β -内酰胺酶基因。根据pMLST测定的9种序列类型，通过RFLP将这些质粒分为9个不同的组。结论：pMLST法是一种简便、快速的IncI1质粒分型方法。本研究表明，pMLST方法有助于描述从动物和人类分离的β -内酰胺酶产生物中特异性耐药质粒的流行病学传播。
Objectives: Plasmids belonging to incompatibility group I1 (IncI1) are widespread in Enterobacteriaceae and are characterized by the presence of a cluster of genes encoding the type IV pili, contributing to the virulence of Shiga-toxigenic Escherichia coli. Recently, IncI1 plasmids were identified in E. coli and Salmonella strains of animal origin as responsible for the dissemination of beta-lactamase genes. Plasmid multilocus sequence typing (pMLST) was developed to discern naturally occurring IncI1 plasmids in homogeneous groups according to their allele assortment.Methods: pMLST was developed by selecting multiple target genes on the available complete IncI1 plasmid DNA sequences. Sixteen plasmids, all assigned to the IncI1 group by the PCR-based replicon typing method, were included in this study. They were analysed for beta-lactamase genes and typed by restriction fragment length polymorphism (RFLP) and pMLST.Results: Sixteen plasmids identified in E. coli and Salmonella isolated from animals and humans in different countries carried bla(CMY-2), bla(CTX-M-15), bla(CTX-M-1), bla(CTX-M-14), bla(TEM-52), bla(SHV-12) or bla(TEM-1) beta-lactamase genes. These plasmids were classified by RFLP in nine different groups corresponding to the nine sequence types determined by pMLST.Conclusions: The pMLST method was suitable for rapid and easy subtyping of IncI1 plasmids. This study demonstrates that the pMLST method can contribute to the epidemiological description of circulation of specific resistance plasmids among beta-lactamase producers isolated from animals and humans.