Canadian Research Institute for Food Safety, University of Guelph, Guelph, ON, N1G 2W1, Canada,
Arch Virol. 2014 Sep;159(9):2253-61. doi: 10.1007/s00705-014-2055-x. Epub 2014 Apr 6.
Cronobacter sakazakii, an opportunistic pathogen found in milk-based powdered infant formulae, has been linked to meningitis in infants, with high fatality rates. A set of phages from various environments were purified and tested in vitro against strains of C. sakazakii. Based on host range and lytic activity, the T4-like phage vB_CsaM_GAP161, which belongs to the family Myoviridae, was selected for evaluation of its efficacy against C. sakazakii. Galleria mellonella larvae were used as a whole-animal model for pre-clinical testing of phage efficiency. Twenty-one Cronobacter strains were evaluated for lethality in G. mellonella larvae. Different strains of C. sakazakii caused 0 to 98% mortality. C. sakazakii 3253, with an LD50 dose of ~2.0×10(5) CFU/larva (24 h, 37 °C) was selected for this study. Larvae infected with a dose of 5×LD50 were treated with phage GAP161 (MOI=8) at various time intervals. The mortality rates were as high as 100% in the groups injected with bacteria only, compared to 16.6% in the group infected with bacteria and treated with phage. Phage GAP161 showed the best protective activity against C. sakazakii when the larvae were treated prior to or immediately after infection. The results obtained with heat-inactivated phage proved that the survival of the larvae is not due to host immune stimulation. These results suggest that phage GAP161 is potentially a useful control agent against C. sakazakii. In addition, G. mellonella may be a useful whole-animal model for pre-screening phages for efficacy and safety prior to clinical evaluation in mammalian models.
阪崎克罗诺杆菌是一种存在于以牛奶为基础的配方奶粉中的机会致病菌，已与婴儿脑膜炎有关，死亡率很高。从各种环境中纯化了一组噬菌体，并在体外针对阪崎克罗诺杆菌菌株进行了测试。根据宿主范围和裂解活性，选择 T4 样噬菌体 vB_CsaM_GAP161（属于肌尾噬菌体科）来评估其对阪崎克罗诺杆菌的功效。金蝇幼虫被用作噬菌体功效的临床前测试的整体动物模型。评估了 21 株阪崎克罗诺杆菌对金蝇幼虫的致死率。不同的阪崎克罗诺杆菌菌株导致 0 至 98%的死亡率。阪崎克罗诺杆菌 3253 的 LD50 剂量约为 2.0×10(5)CFU/幼虫（24 小时，37°C），被选为这项研究的菌株。用 5×LD50 剂量感染的幼虫在不同时间间隔用噬菌体 GAP161（MOI=8）处理。仅用细菌注射的组的死亡率高达 100%，而用细菌感染并用噬菌体处理的组的死亡率为 16.6%。噬菌体 GAP161 在幼虫感染前或感染后立即处理时对阪崎克罗诺杆菌显示出最佳的保护活性。用热失活噬菌体获得的结果证明幼虫的存活不是由于宿主免疫刺激。这些结果表明噬菌体 GAP161 可能是一种对抗阪崎克罗诺杆菌的有用控制剂。此外，金蝇幼虫可能是一种有用的整体动物模型，可用于在哺乳动物模型中临床评估之前对噬菌体的功效和安全性进行预筛选。
