Clinical Epidemiology and Molecular Analysis of Extended-Spectrum-β-Lactamase-Producing Escherichia coli in Nepal: Characteristics of Sequence Types 131 and 648
Clinical Epidemiology and Molecular Analysis of Extended-Spectrum-β-Lactamase-Producing Escherichia coli in Nepal: Characteristics of Sequence Types 131 and 648
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DOI：
10.1128/aac.00270-15
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发表时间：
2015-06-01
影响因子：
4.9
通讯作者：
Tandukar, Sarmila
中科院分区：
文献类型：
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作者：
Sherchan, Jatan Bahadur;Hayakawa, Kayoko;Tandukar, Sarmila
近年来，世界范围内出现了CTX-M型产超广谱β-内酰胺酶(ESBL)的大肠埃希菌。特别是，具有O型抗原25(O25)和序列型131(ST131)的大肠杆菌通常与CTX-M-15ESBL有关，在全球范围内已有越来越多的报道；然而，亚洲关于产生ESBL的大肠杆菌的流行病学报告有限。这项研究包括尼泊尔加德满都Tribhuvan大学教学医院的临床分离的产ESBL大肠埃希菌的患者。对分离株进行全基因组测序，分析其多位点序列类型、亲缘关系、毒力基因类型、O25b-ST131克隆及获得性耐药基因的分布。在研究期间，共鉴定了105例产超广谱β-内酰胺酶的大肠埃希菌，其中大部分(90%)为CTX-M-15阳性。ST段以ST131为主(n=54，占51.4%)，其次为ST648(n=15，占14.3%)。所有ST131菌株均鉴定为O25b-ST131克隆，H30-Rx亚克隆。对三组ST段(ST131、ST648和非ST131/648)进行比较分析。与ST131或非ST131/648菌株相比，ST648菌株对非β-内酰胺类抗生素的耐药率更高，耐药基因的频率更高。ST131的毒力基因最多，其次是ST648。不同组间的临床特征相似。产超广谱β-内酰胺酶的大肠埃希菌38%以上来自门诊，孕妇占产超广谱β-内酰胺酶的病例的24%。我们发现，尼泊尔产超广谱β-内酰胺酶的大肠杆菌对多种抗生素的高耐药性主要是由产CTX-M的ST131和ST648推动的。它们在社区中的广泛流行是一个令人极为关切的问题。
Recently, CTX-M-type extended-spectrum-beta-lactamase (ESBL)-producing Escherichia coli strains have emerged worldwide. In particular, E. coli with O antigen type 25 (O25) and sequence type 131 (ST131), which is often associated with the CTX-M-15 ESBL, has been increasingly reported globally; however, epidemiology reports on ESBL-producing E. coli in Asia are limited. Patients with clinical isolates of ESBL-producing E. coli in the Tribhuvan University teaching hospital in Kathmandu, Nepal, were included in this study. Whole-genome sequencing of the isolates was conducted to analyze multilocus sequence types, phylotypes, virulence genotypes, O25b-ST131 clones, and distribution of acquired drug resistance genes. During the study period, 105 patients with ESBL-producing E. coli isolation were identified, and the majority (90%) of these isolates were CTX-M-15 positive. The most dominant ST was ST131 (n = 54; 51.4%), followed by ST648 (n = 15; 14.3%). All ST131 isolates were identified as O25b-ST131 clones, subclone H30-Rx. Three ST groups (ST131, ST648, and non-ST131/648) were compared in further analyses. ST648 isolates had a proportionally higher resistance to non-beta-lactam antibiotics and featured drug-resistant genes more frequently than ST131 or non-ST131/648 isolates. ST131 possessed the most virulence genes, followed by ST648. The clinical characteristics were similar among groups. More than 38% of ESBL-producing E. coli isolates were from the outpatient clinic, and pregnant patients comprised 24% of ESBL-producing E. coli cases. We revealed that the high resistance of ESBL-producing E. coli to multiple classes of antibiotics in Nepal is driven mainly by CTX-M-producing ST131 and ST648. Their immense prevalence in the communities is a matter of great concern.