Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa; Department of Veterinary Public Health and Preventive Medicine, College of Veterinary Medicine, Michael Okpara University of Agriculture, Umudike, Abia State, Nigeria.
Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa; Department of Basic Veterinary Sciences, School of Veterinary Medicine, Faculty of Medical Sciences, University of the West Indies, St. Augustine, Trinidad and Tobago.
Prev Vet Med. 2022 Aug;205:105681. doi: 10.1016/j.prevetmed.2022.105681. Epub 2022 May 26.
In South Africa, there is a shortage of epidemiologic data on Shiga toxin-producing Escherichia coli (STEC) in the beef production chain. This study was conducted to characterise STEC isolates originating from three studies conducted in a cattle feedlot, beef abattoirs and retail outlets in Gauteng province, South Africa. Polymerase chain reaction was used to detect virulence genes, the Epsilometer test to assess antimicrobial susceptibility, pulsed-field gel electrophoresis (PFGE) to investigate genetic relatedness of isolates, and conventional serotyping for phenotypic identification. Amongst the 86 STEC isolates, the eaeA gene was detected in 20 (23%), and 26 different serogroups were identified, including the clinically important O8, O174, O2, 020 and O117. The majority of the isolates (95%; 82/86) exhibited resistance to one or more antimicrobial agents, and 30 of the isolates (35%) exhibited multi-drug resistance (MDR), being resistant to at least three antimicrobial classes. The PFGE patterns showed a highly diverse but related STEC population, with 45 distinct patterns and evidence of horizontal transmission along the beef production chain. This is significant because it demonstrates continual environmental contamination and risk of contamination along the beef production chain and the food chain. To our knowledge, this is the first study that provides evidence of horizontal transmission of STEC along the beef production chain in South Africa. This epidemiological information could facilitate the development of a proactive strategy for reducing potential foodborne outbreaks and transmission of antimicrobial resistant pathogens in the food chain.
在南非，牛肉生产链中关于产志贺毒素大肠杆菌（STEC）的流行病学数据匮乏。本研究旨在对源于南非豪登省牛饲料场、牛肉屠宰场和零售点的三项研究中分离的 STEC 菌株进行特征描述。采用聚合酶链反应（PCR）检测毒力基因，埃希氏菌抑制试验（Epsilometer test）评估抗菌药物敏感性，脉冲场凝胶电泳（PFGE）分析分离株的遗传相关性，常规血清分型进行表型鉴定。在 86 株 STEC 分离株中，检测到 eaeA 基因 20 株（23%），鉴定出 26 种不同的血清型，包括临床重要的 O8、O174、O2、O20 和 O117。大多数分离株（95%；82/86）对一种或多种抗菌药物表现出耐药性，30 株（35%）表现出多药耐药性（MDR），至少对三种抗菌药物类别耐药。PFGE 模式显示 STEC 种群高度多样化但具有相关性，有 45 种不同的模式，并且证据表明沿牛肉生产链存在水平传播。这很重要，因为它表明在牛肉生产链和食物链中持续存在环境污染和污染风险。据我们所知，这是首次在南非提供有关 STEC 沿牛肉生产链发生水平传播的证据的研究。这些流行病学信息可以促进制定积极的策略，以减少食源性爆发和食物链中抗微生物病原体的传播。
