Nicolas-Chanoine Marie-Hélène, Blanco Jorge, Leflon-Guibout Véronique, Demarty Raphael, Alonso Maria Pilar, Caniça Maria Manuela, Park Yeon-Joon, Lavigne Jean-Philippe, Pitout Johann, Johnson James R
Service de Microbiologie, Hôpital AP-HP Beaujon, 92110 Clichy, France.
J Antimicrob Chemother. 2008 Feb;61(2):273-81. doi: 10.1093/jac/dkm464. Epub 2007 Dec 11.
Concomitant with the recent emergence of CTX-M-type extended-spectrum beta-lactamases (ESBLs), Escherichia coli has become the enterobacterial species most affected by ESBLs. Multiple locales are encountering CTX-M-positive E. coli, including specifically CTX-M-15. To gain insights into the mechanism underlying this phenomenon, we assessed clonality and diversity of virulence profiles within an international collection of CTX-M-15-positive E. coli.
Forty-one ESBL-positive E. coli isolates from eight countries and three continents (Europe, Asia and North America) were selected for study based on suspected clonality. Phylogenetic group, ERIC2 PCR profile, O H serotype, AmpC variant and antibiotic susceptibility were determined. Multilocus sequence typing (MLST) and PFGE provided additional discrimination. Virulence potential was inferred by detection of 46 virulence factor (VF) genes.
Thirty-six (88%) of the 41 E. coli isolates exhibited the same set of core characteristics: phylogenetic group B2, ERIC2 PCR profile 1, serotype O25:H4, AmpC EC6, ciprofloxacin resistance and MLST profile ST131. By PFGE, the 36 isolates constituted one large cluster at the 68% similarity level; this comprised 17 PFGE groups (defined at 85% similarity), some of which included strains from different countries. The 36 isolates exhibited highly (91% to 100%) similar VF profiles.
We describe a broadly disseminated, CTX-M-15-positive and virulent E. coli clonal group with highly homogeneous virulence genotypes and subgroups exhibiting highly similar PFGE profiles, suggesting recent emergence. Understanding how this clone has emerged and successfully disseminated within the hospital and community, including across national boundaries, should be a public health priority.
随着CTX-M型超广谱β-内酰胺酶（ESBLs）的近期出现，大肠埃希菌已成为受ESBLs影响最严重的肠杆菌种。多个地区都发现了CTX-M阳性的大肠埃希菌，特别是CTX-M-15。为深入了解这一现象背后的机制，我们评估了国际范围内CTX-M-15阳性大肠埃希菌的克隆性和毒力谱多样性。
基于疑似克隆性，从欧洲、亚洲和北美洲三大洲八个国家选取了41株ESBL阳性大肠埃希菌分离株进行研究。确定了系统发育群、ERIC2 PCR图谱、O:H血清型、AmpC变异体和抗生素敏感性。多位点序列分型（MLST）和脉冲场凝胶电泳（PFGE）提供了进一步的鉴别。通过检测46个毒力因子（VF）基因推断毒力潜力。
41株大肠埃希菌分离株中有36株（88%）表现出相同的一组核心特征：系统发育群B2、ERIC2 PCR图谱1、血清型O25:H4、AmpC EC6、对环丙沙星耐药以及MLST图谱ST131。通过PFGE，36株分离株在68%的相似性水平上构成一个大簇；这包括17个PFGE组（在85%的相似性水平上定义），其中一些组包括来自不同国家的菌株。36株分离株表现出高度（91%至100%）相似的VF图谱。
我们描述了一个广泛传播的、CTX-M-15阳性且有毒力的大肠埃希菌克隆群，其毒力基因型高度同质，亚组表现出高度相似的PFGE图谱，表明其近期出现。了解这个克隆群是如何出现并在医院和社区内成功传播的，包括跨国传播，应是公共卫生的优先事项。
