United States Department of Agriculture, Agricultural Research Service, U.S. Meat Animal Research Center, Meat Safety and Quality Research Unit, State Spur 18D, Clay Center, NE 68933, USA.
United States Department of Agriculture, Agricultural Research Service, U.S. Meat Animal Research Center, Meat Safety and Quality Research Unit, State Spur 18D, Clay Center, NE 68933, USA.
J Food Prot. 2024 Jun;87(6):100273. doi: 10.1016/j.jfp.2024.100273. Epub 2024 Apr 8.
Cattle are considered a primary reservoir of Shiga toxin (stx)-producing Escherichia coli that cause enterohemorrhagic disease (EHEC), and contaminated beef products are one vehicle of transmission to humans. However, animals entering the beef harvest process originate from differing production systems: feedlots, dairies, and beef breeding herds. The objective of this study was to determine if fed cattle, cull dairy, and or cull beef cattle carry differing proportions and serogroups of EHEC at harvest. Feces were collected via rectoanal mucosal swabs (RAMSs) from 1,039 fed cattle, 1,058 cull dairy cattle, and 1,018 cull beef cattle at harvest plants in seven U.S. states (CA, GA, NE, PA, TX, WA, and WI). The proportion of the stx gene in feces of fed cattle (99.04%) was not significantly different (P > 0.05) than in the feces of cull dairy (92.06%) and cull beef (91.85%) cattle. When two additional factors predictive of EHEC (intimin and ecf1 genes) were considered, EHEC was significantly greater (P < 0.05) in fed cattle (77.29%) than in cull dairy (47.54%) and cull beef (38.51%) cattle. The presence of E. coli O157:H7 and five common non-O157 EHEC of serogroups O26, O103, O111, O121, and O145 was determined using molecular analysis for single nucleotide polymorphisms (SNPs) followed by culture isolation. SNP analysis identified 23.48%, 17.67%, and 10.81% and culture isolation confirmed 2.98%, 3.31%, and 3.00% of fed, cull dairy, and cull beef cattle feces to contain one of these EHEC, respectively. The most common serogroups confirmed by culture isolation were O157, O103, and O26. Potential EHEC of fourteen other serogroups were isolated as well, from 4.86%, 2.46%, and 2.01% of fed, cull dairy, and cull beef cattle feces, respectively; with the most common being serogroups O177, O74, O98, and O84. The identification of particular EHEC serogroups in different types of cattle at harvest may offer opportunities to improve food safety risk management.
牛被认为是产志贺毒素（stx）大肠杆菌的主要宿主，这些大肠杆菌会导致肠出血性疾病（EHEC），受污染的牛肉产品是人类感染的一个途径。然而，进入牛肉收获过程的动物来自不同的生产系统：饲养场、奶牛场和肉牛养殖场。本研究的目的是确定在收获时，育肥牛、淘汰奶牛和/或淘汰肉牛是否携带不同比例和血清群的 EHEC。通过直肠-肛门黏膜拭子（RAMS）从美国七个州（加利福尼亚州、佐治亚州、内布拉斯加州、宾夕法尼亚州、得克萨斯州、华盛顿州和威斯康星州）的 1039 头育肥牛、1058 头淘汰奶牛和 1018 头淘汰肉牛中采集粪便。育肥牛粪便中 stx 基因的比例（99.04%）与淘汰奶牛（92.06%）和淘汰肉牛（91.85%）粪便中 stx 基因的比例无显著差异（P＞0.05）。当考虑到另外两个预测 EHEC 的因素（细胞紧密素和 ecf1 基因）时，育肥牛（77.29%）中 EHEC 的比例显著高于淘汰奶牛（47.54%）和淘汰肉牛（38.51%）。使用分子分析单核苷酸多态性（SNP），然后进行培养分离，确定了大肠杆菌 O157:H7 和五个常见的非 O157 EHEC 的血清群 O26、O103、O111、O121 和 O145 的存在。SNP 分析确定了 23.48%、17.67%和 10.81%，培养分离证实了 2.98%、3.31%和 3.00%的育肥牛、淘汰奶牛和淘汰肉牛粪便中分别含有一种 EHEC。通过培养分离证实的最常见的血清群是 O157、O103 和 O26。还从 4.86%、2.46%和 2.01%的育肥牛、淘汰奶牛和淘汰肉牛粪便中分离出了其他 14 个血清群的潜在 EHEC，最常见的血清群是 O177、O74、O98 和 O84。在收获时不同类型的牛中鉴定出特定的 EHEC 血清群，可能为改善食品安全风险管理提供机会。
