Molecular Typing of CTX-M-Producing Escherichia coli Isolates from Environmental Water, Swine Feces, Specimens from Healthy Humans, and Human Patients
Molecular Typing of CTX-M-Producing Escherichia coli Isolates from Environmental Water, Swine Feces, Specimens from Healthy Humans, and Human Patients
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DOI：
10.1128/aem.01740-13
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发表时间：
2013-10-01
影响因子：
4.4
通讯作者：
Chen, Gong-Xiang
中科院分区：
文献类型：
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作者：
Hu, Yan-Yan;Cai, Jia-Chang;Chen, Gong-Xiang
产CTX-M大肠埃希菌是产超广谱β-内酰胺酶（ESBL）的主要大肠埃希菌。世界各地的大肠杆菌。本研究对139株产CTX-M的大肠杆菌进行了分子分型。大肠埃希菌分离株，ESBLs表型阳性，从环境水，猪，健康人，和住院患者在中国杭州。对头孢菌素类和氟喹诺酮类抗生素的耐药谱进行了测定。分离株对头孢噻肟和头孢曲松的耐药率为100%，而对头孢西丁、头孢吡肟和头孢他啶的敏感性较高。无论来源，共有61.9%（86/139）的分离株对氟喹诺酮类药物高度耐药。PCR和DNA测序结果表明，CTX-M-9组基因以bla（CTX-M-14）为主，CTX-M-1组基因以bla（CTX-M-15）和bla（CTX-M-55）为主。来自所有来源的CTX-M型分离株属于CTX-M-1或CTX-M-9组，最常与流行病相关。通过系统发育分组、脉冲场凝胶电泳（PFGE）和多位点序列分型（MLST）对分离株进行分子同源性分析，结果表明优势克隆属于B2-ST 131、D-ST 648、D-ST 38或A-CC 10。这四种序列类型（ST）是在E.大肠杆菌从人类和环境水体中分离，表明人类和水生环境之间频繁和持续的隔室间传播。在本研究中鉴定了七种新的序列类型。本研究首次报道了产CTX-M大肠杆菌的分子同源性分析。从水、猪、健康人和住院病人中收集的大肠杆菌分离株，表明环境中的病原体可能来源于人和动物。
CTX-M-producing Escherichia coli is the predominant type of extended-spectrum beta-lactamase (ESBL)-producing E. coli worldwide. In this study, molecular typing was conducted for 139 CTX-M-producing E. coli isolates, phenotypically positive for ESBLs, isolated from environmental water, swine, healthy humans, and hospitalized patients in Hangzhou, China. The antibiotic resistance profiles of the isolates for the cephalosporins and fluoroquinolones were determined. The isolates showed 100% resistance to cefotaxime and ceftriaxone while maintaining relatively high susceptibility to cefoxitin, cefepime, and ceftazidime. A total of 61.9% (86/139) of the isolates, regardless of origin, showed high resistance to fluoroquinolones. PCRs and DNA sequencing indicated that bla(CTX-M-14) was the most prevalent CTX-M-9 group gene and that bla(CTX-M-15) and bla(CTX-M-55) were the dominant CTX-M-1 group genes. Isolates from all sources with CTX-M types belonging to the CTX-M-1 or CTX-M-9 group were most frequently associated with epidemics. Molecular homology analysis of the isolates, conducted by phylogenetic grouping, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST), demonstrated that the dominant clones belonged to B2-ST131, D-ST648, D-ST38, or A-CC10. These four sequence types (STs) were discovered in E. coli isolates both from humans and from environmental water, suggesting frequent and continuous intercompartment transmission between humans and the aquatic environment. Seven novel sequence types were identified in the current study. In conclusion, this study is the first to report the molecular homology analysis of CTX-M-producing E. coli isolates collected from water, swine, and healthy and hospitalized humans, suggesting that pathogens in the environment might originate both from humans and from animals.