Rivera Dácil, Toledo Viviana, Pillo Francisca DI, Dueñas Fernando, Tardone Rodolfo, Hamilton-West Christopher, Vongkamjan Kitiya, Wiedmann Martin, Switt Andrea I Moreno
1 Escuela de Medicina Veterinaria, Facultad de Ecología y Recursos Naturales, Universidad Andres Bello, Santiago 8370146, Chile.
2 Departamento de Ciencia de los Alimentos y Tecnología Química, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile.
J Food Prot. 2018 Feb;81(2):272-278. doi: 10.4315/0362-028X.JFP-17-075.
The genus Salmonella has more than 2,600 serovars, and this trait is important when considering interventions for Salmonella control. Bacteriophages that are used for biocontrol must have an exclusively lytic cycle and the ability to lyse several Salmonella serovars under a wide range of environmental conditions. Salmonella phages were isolated and characterized from 34 backyard production systems (BPSs) with a history of Salmonella infections. BPSs were visited once, and cloacal or fecal samples were processed for phage isolation. Four hosts, Salmonella serovars Enteritidis, Heidelberg, Infantis, and Typhimurium, were used for phage isolation. The host range of the phages was later characterized with a panel of 23 Salmonella serovars (serovar diversity set) and 31 isolates obtained from the same farms (native set). Genetic relatedness for 10 phages with a wide host range was characterized by restriction fragment length polymorphism, and phages clustered based on the host range. We purified 63 phages, and 36 phage isolates were obtained on Salmonella Enteritidis, 16 on Salmonella Heidelberg, and 11 on Salmonella Infantis. Phages were classified in three clusters: (i) phages with a wide host range (cluster I), (ii) phages that lysed the most susceptible Salmonella serovars (serogroup D) and other isolates (cluster II), and (iii) phages that lysed only isolates of serogroup D (cluster III). The most susceptible Salmonella serovars were Enteritidis, Javiana, and Dublin. Seven of 34 farms yielded phages with a wide host range, and these phages had low levels of genetic relatedness. Our study showed an adaptation of the phages in the sampled BPSs to serogroup D Salmonella isolates and indicated that isolation of Salmonella phages with wide host range differs by farm. A better understanding of the factors driving the Salmonella phage host range could be useful when designing risk-based sampling strategies to obtain phages with a wide lytic host range for biocontrol purposes.
沙门氏菌属有2600多个血清型，在考虑沙门氏菌控制干预措施时，这一特性很重要。用于生物防治的噬菌体必须具有专一的裂解周期，并且能够在广泛的环境条件下裂解多种沙门氏菌血清型。从34个有沙门氏菌感染史的后院生产系统（BPS）中分离并鉴定了沙门氏菌噬菌体。对BPS进行了一次走访，并对泄殖腔或粪便样本进行处理以分离噬菌体。使用四种宿主，即肠炎沙门氏菌、海德堡沙门氏菌、婴儿沙门氏菌和鼠伤寒沙门氏菌来分离噬菌体。随后，用一组23种沙门氏菌血清型（血清型多样性集）和从同一农场获得的31个分离株（本地集）对噬菌体的宿主范围进行了鉴定。通过限制性片段长度多态性对10种宿主范围广泛的噬菌体的遗传相关性进行了鉴定，噬菌体根据宿主范围聚类。我们纯化了63种噬菌体，在肠炎沙门氏菌上获得了36个噬菌体分离株，在海德堡沙门氏菌上获得了16个，在婴儿沙门氏菌上获得了11个。噬菌体分为三个簇：（i）宿主范围广泛的噬菌体（簇I），（ii）裂解最易感沙门氏菌血清型（D血清群）和其他分离株的噬菌体（簇II），以及（iii）仅裂解D血清群分离株的噬菌体（簇III）。最易感的沙门氏菌血清型是肠炎沙门氏菌、贾维亚纳沙门氏菌和都柏林沙门氏菌。34个农场中有7个产生了宿主范围广泛的噬菌体，这些噬菌体的遗传相关性较低。我们的研究表明，采样的BPS中的噬菌体适应了D血清群沙门氏菌分离株，并表明不同农场分离宿主范围广泛的沙门氏菌噬菌体的情况有所不同。在设计基于风险抽样策略以获得用于生物防治目的的具有广泛裂解宿主范围的噬菌体时，更好地了解驱动沙门氏菌噬菌体宿主范围的因素可能会有所帮助。
