Extensively Drug-Resistant Escherichia coli Sequence Type 1642 Carrying an IncX3 Plasmid Containing the blaKPC-2 Gene Associated with Transposon Tn4401a
Extensively Drug-Resistant Escherichia coli Sequence Type 1642 Carrying an IncX3 Plasmid Containing the blaKPC-2 Gene Associated with Transposon Tn4401a
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DOI：
10.3343/alm.2018.38.1.17
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发表时间：
2018-01-01
影响因子：
4.9
通讯作者：
Jeong, Seok Hoon
中科院分区：
文献类型：
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作者：
Jeong, Seri;Kim, Jung Ok;Jeong, Seok Hoon
背景：携带bla（KPC）基因的广泛耐药（XDR）肠杆菌科已成为全球主要的治疗问题。方法：采用药敏试验、PCR、多位点序列分型（MLST）和全基因组测序等方法，对1642株产KPC-2碳青霉烯酶的大肠埃希菌进行质粒全序列分析。结果：分离株对大多数可用的抗生素耐药，包括美罗培南、氨苄西林、头孢曲松、庆大霉素和环丙沙星，但对替加环素和粘菌素敏感。经MLST鉴定为罕见的ST 1642。分离物携带四种质粒：第一个69-kb的接合IncX 3质粒在截短的Tn 4401 a转座子和bla（SHV-11）内含有blaKPC-2，具有重复的接合元件。第二个142-kb质粒具有由IncQ、IncFIA和IncIB组成的多复制子，携带bla（TEM-1b）和两个1类整合子。该质粒还含有多种其他的耐药基因，包括aadA 5、dfrA 17、mph（A）、sul 1、泰特（B）、aac（3 '）-IId、strA、strB和sul 2。与持续感染相关的大肠杆菌菌株显示携带IncX 3型质粒的bla（KPC-2）和携带1类整合子的多复制子共存，表明其具有引起暴发的潜力。具有额外临床意义的是，在猫中发现的罕见ST 1642可能构成人类感染源。
Background: Extensively drug-resistant (XDR) Enterobacteriaceae carrying the bla(KPC) gene have emerged as a major global therapeutic concern. The purpose of this study was to analyze the complete sequences of plasmids from KPC-2 carbapenemase-producing XDR Escherichia coli sequence type (ST) 1642 isolates.Methods: We performed antimicrobial susceptibility testing, PCR, multilocus sequence typing (MLST), and whole-genome sequencing to characterize the plasmid-mediated KPC-2-producing E. coli clinical isolates.Results: The isolates were resistant to most available antibiotics, including meropenem, ampicillin, ceftriaxone, gentamicin, and ciprofloxacin, but susceptible to tigecycline and colistin. The isolates were identified as the rare ST1642 by MLST. The isolates carried four plasmids: the first 69-kb conjugative IncX3 plasmid harbors blaKPC-2 within a truncated Tn4401a transposon and bla(SHV-11) with duplicated conjugative elements. The second 142-kb plasmid with a multireplicon consisting of IncQ, IncFIA, and IncIB carries bla(TEM-1b) and two class 1 integrons. This plasmid also harbors a wide variety of additional antimicrobial resistance genes including aadA5, dfrA17, mph(A), sul1, tet(B), aac(3')-IId, strA, strB, and sul2.Conclusions: The complete sequence analysis of plasmids from an XDR E. coli strain related to persistent infection showed the coexistence of a bla(KPC-2)-carrying IncX3-type plasmid and a class 1 integron-harboring multireplicon, suggesting its potential to cause outbreaks. Of additional clinical significance, the rare ST1642, identified in a cat, could constitute the source of human infection.