Genomic Characterization of β-Glucuronidase-Positive Escherichia coli O157:H7 Producing Stx2a.
Genomic Characterization of β-Glucuronidase-Positive Escherichia coli O157:H7 Producing Stx2a.
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DOI：
10.3201/eid2412.180404
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发表时间：
2018-12
影响因子：
11.8
通讯作者：
Hayashi T
中科院分区：
文献类型：
--
作者：
Ogura Y;Seto K;Morimoto Y;Nakamura K;Sato MP;Gotoh Y;Itoh T;Toyoda A;Ohnishi M;Hayashi T
在产生志贺毒素（Stx）的大肠杆菌（STEC） O157:H7菌株中，产生Stx2a的菌株引起更严重的疾病。显示β-葡萄糖醛酸酶阳性表型的非典型产大肠杆菌O157:H7株（GP产大肠杆菌O157:H7）很少从人身上分离出来，主要是从无症状或轻度感染的人身上分离出来的；尚未报道产生stx2a的菌株。我们从一名出血性腹泻患者中分离出一株GP STEC O157:H7菌株（PV15-279），该菌株除了产生Stx1a和Stx2c外，还产生Stx2a。与其他STEC O157菌株的基因组比较显示，PV15-279最近从日本流行的stx1a/stx2c阳性GP STEC O157:H7克隆中出现。典型菌株（β-葡萄糖醛酸酶阴性）和GP产STEC O157:H7主要毒力基因共享，PV15-279产stx2能力与典型STEC O157:H7菌株相当；因此，PV15-279具有与典型的产志在大肠杆菌O157:H7相似的潜在毒力。这项研究揭示了GP O157:H7作为高致病性产志贺毒素大肠杆菌克隆来源的重要性。
Among Shiga toxin (Stx)–producing Escherichia coli (STEC) O157:H7 strains, those producing Stx2a cause more severe diseases. Atypical STEC O157:H7 strains showing a β-glucuronidase–positive phenotype (GP STEC O157:H7) have rarely been isolated from humans, mostly from persons with asymptomatic or mild infections; Stx2a-producing strains have not been reported. We isolated, from a patient with bloody diarrhea, a GP STEC O157:H7 strain (PV15-279) that produces Stx2a in addition to Stx1a and Stx2c. Genomic comparison with other STEC O157 strains revealed that PV15-279 recently emerged from the stx1a/stx2c-positive GP STEC O157:H7 clone circulating in Japan. Major virulence genes are shared between typical (β-glucuronidase–negative) and GP STEC O157:H7 strains, and the Stx2-producing ability of PV15-279 is comparable to that of typical STEC O157:H7 strains; therefore, PV15-279 presents a virulence potential similar to that of typical STEC O157:H7. This study reveals the importance of GP O157:H7 as a source of highly pathogenic STEC clones.