Department of Food Science and Engineering, Ocean University of China, Qingdao 266003, P. R. China.
Department of Food Science and Engineering, Ocean University of China, Qingdao 266003, P. R. China.
Poult Sci. 2020 Jul;99(7):3643-3654. doi: 10.1016/j.psj.2020.03.051. Epub 2020 Apr 26.
Salmonella is regarded as the predominant cause of foodborne illnesses worldwide, and the increase of these antimicrobial-resistant strains makes it more difficult to prevent. On this occasion, bacteriophages (phages) stand out as an alternative biocontrol agent with high efficiency and low mutation rates. Salmonella phages have confronted challenges to counteract with more than 2,500 serovars of Salmonella spp. and overcome the universality of antibiotics to different species, and thus, broad-host-range phages infecting Salmonella spp. are urgently required to realize precise poultry treatment or clinical therapy. First, phage STP4-a was screened to have a broad host range through bioinformatics analysis, and then the host range assay proved that phage STP4-a could inhibit 88 out of 91 Salmonella strains. Then, in silico analysis excluded the possibility of phage STP4-a possessing any known lysogeny factors, toxins, pathogen-related genes, or foodborne allergens, and oral toxicity studies further ensured the safety of unknown factors or suspected risks. In addition, strong inhibition effects of phage STP4-a were seen on both single Salmonella strain and multiple Salmonella strains in vitro, reducing 3-5 log in 30 min. Phage STP4-a could survive and keep more than 50% activity in simulated stomach or intestine environments in vitro. In terms of antimicrobial activities in chickens, pretreatment with phage STP4-a was the most efficient approach to Salmonella biocontrol, non-detectable in feces during the 14-day experimental period. Therefore, phage STP4-a was an extremely broad-host-range and safe biocontrol agent, performing its potential as a food additive or therapeutic drug in poultry industry.
沙门氏菌被认为是全球食源性疾病的主要病原体，而这些具有抗药性的菌株的增加使得预防变得更加困难。在这种情况下，噬菌体（phages）作为一种高效且突变率低的替代生物控制剂脱颖而出。沙门氏菌噬菌体已经面临着对抗超过 2500 种血清型的沙门氏菌的挑战，并克服了抗生素对不同物种的普遍性，因此，广泛宿主范围的噬菌体感染沙门氏菌迫在眉睫，以实现对家禽的精确治疗或临床治疗。首先，通过生物信息学分析筛选出具有广泛宿主范围的噬菌体 STP4-a，然后通过宿主范围测定证明噬菌体 STP4-a 可以抑制 91 株沙门氏菌中的 88 株。然后，计算机分析排除了噬菌体 STP4-a 具有任何已知溶原性因子、毒素、病原体相关基因或食源性过敏原的可能性，口服毒性研究进一步确保了未知因素或可疑风险的安全性。此外，噬菌体 STP4-a 在体外对单一和多种沙门氏菌菌株均表现出强烈的抑制作用，在 30 分钟内减少了 3-5 个对数。噬菌体 STP4-a 可以在体外模拟的胃或肠道环境中存活并保持超过 50%的活性。就噬菌体 STP4-a 在鸡中的抗菌活性而言，预处理是控制沙门氏菌的最有效方法，在 14 天的实验期间粪便中无法检测到。因此，噬菌体 STP4-a 是一种极其广泛宿主范围和安全的生物控制剂，具有作为家禽业食品添加剂或治疗药物的潜力。
