Key Laboratory of Environment Correlative Dietology, Huazhong Agricultural University, Wuhan, 430070, China.
College of Food Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
Arch Microbiol. 2022 Sep 3;204(10):597. doi: 10.1007/s00203-022-03208-x.
Salmonella and Escherichia coli are important foodborne pathogens, forming bacterial biofilms that contribute to their virulence, antimicrobial resistance, and survival on surfaces. Broad lytic phages are promising alternatives to conventional technologies for pathogen biocontrol and reducing biofilms. Herein, we isolated and characterized a novel polyvalent phage STP55 that not only lyse some serotypes of Salmonella, but also some E. coli strains. It had a wide range of pH (4-12) and thermal (30-60 °C) tolerances. The latent time was determined to be 10 min in the one-step growth experiment. Morphological observations by transmission electron microscopy and phylogenetic analysis using terminase gene classified STP55 to family Ackermannviridae in the order Caudovirales, with a complex tail structure. The genome was found to comprise 157,708 bp double-stranded DNA, with 44.57% GC content, 207 predicted ORFs and with no genes associated with antibiotic resistance, toxins, lysogeny, and virulence factors. Particularly, phage STP55 was able to inhibit single- and dual-species biofilms formation by S. Typhimurium ATCC 14028 and E. coli O157: H7, with a reduction percentage of 51.0%, 47.8% and 52.8%, respectively. Moreover, more than 65.0%, 72.9% and 46.2% of an established, single- and dual-species biofilms by S. Typhimurium ATCC 14028 and E. coli O157: H7 were removed after 8 h exposure to the phage STP55, respectively. The elimination effect of STP55 on dual-species biofilm formed on lettuce was further observed by SEM. Overall, our results demonstrated that STP55 is a promising antimicrobial against Salmonella and E. coli.
沙门氏菌和大肠杆菌是重要的食源性致病菌，它们形成细菌生物膜，有助于其毒力、抗微生物药物耐药性和在表面的存活。广谱裂解噬菌体是替代传统病原体生物控制和减少生物膜的有前途的方法。本文中，我们分离并鉴定了一种新型多价噬菌体 STP55，它不仅可以裂解某些血清型的沙门氏菌，还可以裂解某些大肠杆菌菌株。它具有广泛的 pH（4-12）和热（30-60°C）耐受性。一步生长实验中潜伏期为 10 分钟。通过透射电子显微镜进行形态观察和使用末端酶基因进行的系统发育分析，将 STP55 分类为 Caudovirales 目中的 Ackermannviridae 科，具有复杂的尾部结构。基因组由 157708bp 双链 DNA 组成，GC 含量为 44.57%，包含 207 个预测的 ORF，并且没有与抗生素耐药性、毒素、溶原性和毒力因子相关的基因。特别是，噬菌体 STP55 能够抑制 S. Typhimurium ATCC 14028 和 E. coli O157:H7 的单种和双种生物膜形成，抑制率分别为 51.0%、47.8%和 52.8%。此外，在用噬菌体 STP55 孵育 8 小时后，分别有超过 65.0%、72.9%和 46.2%的 S. Typhimurium ATCC 14028 和 E. coli O157:H7 建立的单种和双种生物膜被去除。通过 SEM 进一步观察到 STP55 对生菜上形成的双种生物膜的消除作用。总的来说，我们的结果表明 STP55 是一种有前途的抗沙门氏菌和大肠杆菌的抗菌剂。
