College of Food Science and Engineering, Northwest A&F University, Yangling, China.
College of Food Science, Shanxi Normal University, Taiyuan, Shanxi, China.
Foodborne Pathog Dis. 2024 Oct;21(10):624-633. doi: 10.1089/fpd.2023.0098. Epub 2024 Jul 23.
To investigate the epidemiology of Shiga toxin-producing (STEC) in dairy cattle, 975 samples (185 feces, 34 silage, 36 cattle drinking water, 360 raw milk, and 360 teat skin swabs) were collected from two dairy farms in Baoji and Yangling, Shaanxi Province, China, and were screened for STEC. Whole-genome sequencing was used to analyze the genomic characteristics and potential transmission of STEC isolates. A total of 32 samples were contaminated with STEC, including 4.0% (19/479) in Farm A and 2.6% (13/496) in Farm B. Compared with adult cows (4.5%), nonadult cows had a higher rate (21.3%) of STEC colonization. A total of 14 serotypes and 11 multilocus sequence typing were identified in 32 STEC isolates, among which O55:H12 (25.0%) and ST101 (31.3%) were the most predominant, respectively. Six subtypes/combinations were identified, including (53.1%), (15.6%), , +, + (6.3%, for each), and (3.1%). Of 32 STEC isolates, 159 virulence genes and 27 antibiotic resistance genes were detected. Overall, STEC isolates showed low levels of resistance to the 16 antibiotics tested (0-40.6%), with most common resistance to ampicillin (40.6%). The phylogenetic analysis confirmed that STEC in the gut of cattle can be transmitted through feces. The results of this study help to improve our understanding of the epidemiological aspects of STEC in dairy cattle and provide early warning and control of the prevalence and spread of the bacterium.
为了调查产志贺毒素大肠杆菌（STEC）在奶牛中的流行病学，我们从中国陕西省宝鸡市和杨凌区的两个奶牛场采集了 975 份样本（185 份粪便、34 份青贮料、36 份牛饮用水、360 份生牛乳和 360 份乳头皮肤拭子），并对这些样本进行了 STEC 筛查。我们采用全基因组测序技术分析了 STEC 分离株的基因组特征和潜在的传播途径。结果共发现 32 份样本受到 STEC 污染，其中农场 A 中为 4.0%（19/479），农场 B 中为 2.6%（13/496）。与成年奶牛（4.5%）相比，未成年奶牛 STEC 定植率更高（21.3%）。在 32 株 STEC 分离株中鉴定出 14 种血清型和 11 种多位点序列分型，其中 O55:H12（25.0%）和 ST101（31.3%）最为常见。鉴定出 6 种亚型/组合，包括 O111:H21（53.1%）、O103:H2（15.6%）、O111:H21（6.3%，各型）和 O157:H7（3.1%）。32 株 STEC 分离株共检出 159 种毒力基因和 27 种抗生素耐药基因。总的来说，STEC 分离株对所测试的 16 种抗生素表现出低水平的耐药性（0-40.6%），最常见的耐药性是氨苄西林（40.6%）。系统进化分析证实，奶牛肠道中的 STEC 可通过粪便传播。本研究结果有助于提高我们对奶牛中 STEC 流行病学的认识，并为该菌的流行和传播提供早期预警和控制。
