Shiga toxigenic Escherichia coli (STEC) is one of the most important food-borne zoonotic bacterial pathogens responsible for causing gastrointestinal infections, haemorrhagic colitis and haemolytic uremic syndrome. The present study was aimed to isolate and characterize STEC from neonatal dairy calves, animal handlers and their surrounding environment and to establish the genetic relationship among isolates by multilocus sequence typing (MLST). A total number of 115 samples were collected and processed for the isolation of E. coli. The occurrence rate of E. coli was 92.2% (106/115), of which, 18 were typed as STEC. Antibacterial susceptibility analysis revealed 11 (61.1%) strains as multiple drug-resistant (MDR). MLST analysis has delineated 16 sequence types (STs) including nine novel STs. Among STs, ST58 dominated with three strains and was recovered from the environment and neonatal calves. Strains from neonatal calves and humans showed genetic relatedness with significant bootstrap support values indicative of zoonotic transmission potentiality. Analysis of 211 global isolates belonging to 61 STs indicated predominant STs (ST 21, ST 33 and ST 3416) that can be either host-specific (ST 33 and ST 3416) or can be shared among human and bovine hosts (ST 21). The MLST analysis indicates genetic relatedness among isolates and the results predispose inter-host transmission and zoonotic spread.

志贺产毒 大肠杆菌 (STEC) 是最重要的食源性人畜共患细菌病原体之一，可引起胃肠道感染、出血性结肠炎和溶血性尿毒症综合征。本研究旨在从新生奶牛、动物处理人员及其周围环境中分离和表征 STEC，并通过多位点序列分型 (MLST) 建立分离物之间的遗传关系。共收集和处理了 115 个样品，用于分离大肠杆菌。大肠杆菌的发生率为 92.2%（106/115），其中 18 种类型为 STEC。抗菌药敏分析显示 11 (61.1%) 株为多重耐药 (MDR)。MLST 分析描绘了 16 种序列类型 (ST)，包括 9 种新的 ST。在 STs 中，ST58 以三种菌株为主，并从环境和新生小牛中恢复。来自新生小牛和人类的菌株显示出遗传相关性，具有表明人畜共患病传播潜力的显着引导支持值。对属于 61 个 ST 的 211 个全球分离株的分析表明，主要的 ST（ST 21、ST 33 和 ST 3416）可以是宿主特异性的（ST 33 和 ST 3416），也可以在人和牛宿主之间共享（ST 21）。MLST 分析表明分离株之间的遗传相关性，结果易发生宿主间传播和人畜共患病传播。