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张爽, 王丽丽, 杨茜, 付奎元, 李颖, 王会波, 李辉, 王园园, 王凤双, 彭涛, 熊衍文. 北京市某区产2k新亚型志贺毒素大肠埃希菌的检出及其分子特征分析[J]. 疾病监测, 2023, 38(7): 872-877. DOI: 10.3784/jbjc.202302160042
引用本文: 张爽, 王丽丽, 杨茜, 付奎元, 李颖, 王会波, 李辉, 王园园, 王凤双, 彭涛, 熊衍文. 北京市某区产2k新亚型志贺毒素大肠埃希菌的检出及其分子特征分析[J]. 疾病监测, 2023, 38(7): 872-877. DOI: 10.3784/jbjc.202302160042
shu
Zhang Shuang, Wang Lili, Yang Xi, Fu Kuiyuan, Li Ying, Wang Huibo, Li Hui, Wang Yuanyuan, Wang Fengshuang, Peng Tao, Xiong Yanwen. Molecular characterization of Escherichia coli producing a novel Shiga toxin 2k subtype detected in one district of Beijing[J]. Disease Surveillance, 2023, 38(7): 872-877. DOI: 10.3784/jbjc.202302160042
Citation: Zhang Shuang, Wang Lili, Yang Xi, Fu Kuiyuan, Li Ying, Wang Huibo, Li Hui, Wang Yuanyuan, Wang Fengshuang, Peng Tao, Xiong Yanwen. Molecular characterization of Escherichia coli producing a novel Shiga toxin 2k subtype detected in one district of Beijing[J]. Disease Surveillance, 2023, 38(7): 872-877. DOI: 10.3784/jbjc.202302160042
shu

北京市某区产2k新亚型志贺毒素大肠埃希菌的检出及其分子特征分析

Molecular characterization of Escherichia coli producing a novel Shiga toxin 2k subtype detected in one district of Beijing

    摘要
  • 摘要:
      目的  分析北京市某区2013—2021年腹泻监测中，首次自腹泻病例分离的2株非O157产志贺毒素大肠埃希菌（STEC）病原学及分子生物学特征。
      方法  应用实时荧光定量PCR方法筛查腹泻病例标本中的肠道致病菌和病毒，对志贺毒素基因（stx）阳性的标本进行细菌分离培养，所得菌株经生化鉴定后，进行血清凝集和微量肉汤稀释法药敏实验，并进行全基因组测序。根据基因组数据分析菌株血清型、多位点序列分型（MLST）、耐药基因及stx 亚型，并构建系统发生树。
      结果  2021年腹泻监测中，2例中年女性腹泻患者样本显示stx基因阳性，未能确定可疑暴露食品。分离所得2株STEC菌株携带stx亚型分别为stx1a和stx2k。其中，Stx1a-STEC为O45:H6血清型、ST101型，药敏表型为耐氨苄西林＋四环素＋头孢噻肟＋头孢唑林＋庆大霉素＋复方磺胺，携带耐药基因aac(3)-Ⅱd、tetA、lnu(F)、aadA22、aph(6)-Id、sul3、qnrS1、ant(3'')-Ia、blaCTX-M-55，样本同时轮状病毒阳性；Stx2k-STEC为O150:H8血清型、ST906型，对检测的15种抗生素均敏感，未检测出耐药基因。全基因组系统进化分析显示2株分离株与STEC参考株存在较大遗传差异。
      结论  北京市某区存在STEC引起的感染，并检出了志贺毒素2k 新亚型，应加强对STEC的监测。

     

    Abstract:
      Objective  To understand the etiological and molecular characteristics of two strains of non-O157 Escherichia coli producing Shiga toxin (STEC), which were isolated for the first time in the surveillance for diarrhea in one district of Beijing from 2013 to 2021.
      Methods  The stool samples from diarrhea patients were screened for enteropathogenic bacteria and viruses by using real-time PCR. The stx-positive samples were selected for isolation. After biochemical identification, the STEC strains were investigate by serum agglutination, micro-broth dilution assays and whole genome sequencing. Based on whole genomic sequences, serotypes, multi-locus sequence types, drug resistance genes, and stx subtypes were predicted, and the phylogenetic tree were constructed.
      Results  In 2021, the stool samples from two middle-aged women with diarrhea were detected to be positive for stx gene, however, the suspected exposed food could not be identified. Two STEC strains carrying stx1a and stx2k were isolated respectively. The Stx1a-STEC was identified as serotype O45:H6, ST101, with a drug-sensitive phenotype of ampicillin+tetracycline+cefotaxime sodium+cefazolin+gentamicin+compound sulfamethoxazole, which carried resistance genes aac(3)-Ⅱd, tetA, lnu(F), aadA22, aph(6)-Id, sul3, qnrS1, ant(3'')-Ia, blaCTX-M-55. The specimen was also rotavirus positive. The Stx2k-STEC was identified as serotype O150:H8, ST906, it was sensitive to all the tested 15 antibiotics, no resistance gene was detected. Phylogenetic analysis revealed high genetic diversity between the two isolates and STEC reference strains.
      Conclusion  Infections caused by STEC existed in this district of Beijing, and the novel Shiga toxin 2k was detected. The surveillance for STEC should be enhanced.

     

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