Sui Xinxia, Wang Shuyun, Yang Xi, Zhang Peihua, Sun Hui, Bai Xiangning, Xiong Yanwen
National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China.
Clinical Laboratory, Children's Hospital Affiliated to Shandong University, Jinan 250022, China.
Microorganisms. 2025 Mar 28;13(4):783. doi: 10.3390/microorganisms13040783.
Shiga toxin-producing (STEC) is an important pathogen that can cause asymptomatic infections, diarrhea, hemorrhagic colitis (HC), and life-threatening hemolytic uremic syndrome (HUS) in humans. Shiga toxins (Stxs) are the major virulence factors encoded by prophages, which play a crucial role in STEC pathogenesis and evolution. In this study, seven Stx phages were obtained from STEC isolates derived from four asymptomatic food handlers, two diarrheal patients, and one outbreak-related HUS case in China. These phages exhibited three morphologies: an icosahedral head with either a short or a long tail, and an elongated head with a long tail. Of these seven phages, three were sequenced; two showed a complete identity with their respective prophage sequences, while phage phiXuzhou21-Stx2a lacked a 6011 bp region-encoding integrase, excisionase, and hypothetical proteins. Comparative genome analysis revealed that the induced seven phages primarily varied in their regulatory regions, whereas the short-tailed phages showed high similarity in their morphogenesis-related regions. In addition, five of the seven phages demonstrated the ability to convert non-pathogenic strains into Stx-producing transduced strains. Under inducing conditions, Stx expression levels were significantly increased in these transduced strains. These findings underscore the diversity and adaptability of Stx phages and emphasize the importance of understanding their genetic and molecular interactions with host bacteria.
产志贺毒素大肠杆菌（STEC）是一种重要的病原体，可导致人类无症状感染、腹泻、出血性结肠炎（HC）以及危及生命的溶血尿毒综合征（HUS）。志贺毒素（Stxs）是由原噬菌体编码的主要毒力因子，在STEC的发病机制和进化中起关键作用。在本研究中，从中国4名无症状食品处理人员、2名腹泻患者和1例与暴发相关的HUS病例分离出的STEC菌株中获得了7种Stx噬菌体。这些噬菌体呈现出三种形态：具有短尾或长尾的二十面体头部，以及具有长尾的细长头部。在这7种噬菌体中，对3种进行了测序；其中2种与其各自的原噬菌体序列完全相同，而噬菌体phiXuzhou21-Stx2a缺少一个编码整合酶、切除酶和假定蛋白的6011 bp区域。比较基因组分析表明，诱导产生的7种噬菌体主要在其调控区域存在差异，而短尾噬菌体在其形态发生相关区域表现出高度相似性。此外，7种噬菌体中有5种表现出将非致病菌株转化为产Stx转导菌株的能力。在诱导条件下，这些转导菌株中Stx的表达水平显著增加。这些发现强调了Stx噬菌体的多样性和适应性，并强调了了解它们与宿主细菌的遗传和分子相互作用的重要性。
