Molecular Epidemiology of CTX-M-Producing Escherichia coli Isolates at a Tertiary Medical Center in Western Pennsylvania
Molecular Epidemiology of CTX-M-Producing Escherichia coli Isolates at a Tertiary Medical Center in Western Pennsylvania
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DOI：
10.1128/aac.00533-09
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发表时间：
2009-11-01
影响因子：
4.9
通讯作者：
Doi, Yohei
中科院分区：
文献类型：
--
作者：
Sidjabat, Hanna E.;Paterson, David L.;Doi, Yohei
采用表型和基因型相结合的方法，研究了2007年至2008年在宾夕法尼亚州匹兹堡市的一家医疗中心鉴定为产超广谱β-内酰胺酶（ESBLs）的70株独特的大肠埃希菌临床分离株。57株（81%）产CTX-M型ESBLs，其中CTX-M-15型ESBLs占优势（n = 46）。还鉴定了产生CTX-M-2、CTX-M-9、CTX-M-14和CTX-M-65的分离株。一株产CTX-M的菌株同时产生CMY-2头孢菌素酶。10株（14%）产生SHV型ESBLs，SHV-5或SHV-7。两个分离株仅产生CMY-2或CMY-32。脉冲场凝胶电泳显示存在两个主要的CTX-M-15产生菌群。大肠杆菌B2型15株，A型19株。在4株能转移携带bla（CTX-M-15）质粒的B_2型分离株中，有3株与A型分离株质粒的指纹图谱相关（>60%）。在B2型中，所有产CTX-M-15的分离株以及3株产CTX-M-14的分离株、2株产SHV-5的分离株和1株产SHV-7的分离株均属于由血清型O25：H4和序列型131定义的国际流行性克隆。9株产CTX-M-15的大肠杆菌中有8株的质粒被检出。大肠杆菌A型分离株之间的亲缘关系很近，在两株D型分离株中也发现了这种质粒，这表明携带有CTX-M-15的bla质粒在两个D型分离株之间存在水平转移。我们的研究结果强调需要进一步研究产CTX-M大肠杆菌的流行病学和毒力。大肠杆菌在美国。
A combination of phenotypic and genotypic methods was used to investigate 70 unique Escherichia coli clinical isolates identified as producing extended-spectrum beta-lactamases (ESBLs) at a medical center in Pittsburgh, PA, between 2007 and 2008. Fifty-seven isolates (81%) produced CTX-M-type ESBLs, among which CTX-M-15 was predominant (n = 46). Isolates producing CTX-M-2, -9, -14, and -65 were also identified. One CTX-M-producing isolate coproduced CMY-2 cephalosporinase. Ten isolates (14%) produced SHV-type ESBLs, either SHV-5 or SHV-7. Two isolates produced only CMY-2 or -32. Pulsed-field gel electrophoresis revealed the presence of two major clusters of CTX-M-15-producing E. coli isolates, one in phylotype B2 (n = 15) and the other in phylotype A (n = 19). Of four phylotype B2 isolates that were able to transfer the bla(CTX-M-15)-carrying plasmids, three showed fingerprints related (>60%) to those of plasmids from phylotype A isolates. In phylotype B2, all CTX-M-15-producing isolates, as well as three isolates producing CTX-M-14, two producing SHV-5, and one producing SHV-7, belonged to the international epidemic clone defined by serotype O25:H4 and sequence type 131. The plasmids from eight of nine CTX-M-15-producing E. coli isolates of phylotype A that were examined were highly related to each other and were also found in two isolates belonging to phylotype D, suggesting horizontal transfer of this bla CTX-M-15-carrying plasmid between phylotypes. Our findings underscore the need to further investigate the epidemiology and virulence of CTX-M-producing E. coli in the United States.