Kim Eo-Jin, Ryu Sangryeol, Lim Jeong-A
Research Group of Food Safety and Distribution, Korea Food Research Institute, Wanju, Republic of Korea.
Department of Food Science and Biotechnology, Chung-Ang University, Anseong, Republic of Korea.
Front Microbiol. 2025 May 19;16:1594533. doi: 10.3389/fmicb.2025.1594533. eCollection 2025.
is a major foodborne pathogen that causes intestinal diseases leading to severe illness. In particular, contamination in fresh produce presents a significant risk, because there are no additional sterilization processes before consumption. In this study, we characterized two novel bacteriophages, vB_EcoS_LEC2 and vB_EcoS_LEC10, and explored their use as a phage cocktail to control naturally occurring contamination in fresh foods.
Two phages were isolated, and their antimicrobial activity and target bacterial spectrum were analyzed. The efficacy of a two-phage cocktail was evaluated against O157:H7 strain mixtures and naturally occurring, unidentified present on commercially available vegetables. The bacterial receptors recognized by the phages were identified using receptor-deficient mutants. The genome sequences of the two phages were compared, focusing on receptor-binding protein genes.
Characterizations revealed that both phages belonged to the family and were stable under various temperatures and pH conditions. The phages were confirmed to be strictly lytic, exhibiting short latent periods of 15 and 10 min and burst sizes of 22 and 189 phage particles per infected cell for LEC2 and LEC10, respectively. LEC2 and LEC10 exhibited distinct antimicrobial spectra, each with a broad but complementary host range among strains. Combining the two phages into a cocktail leveraged their complementary host specificities, broadening the overall host range and enhancing bacterial lysis against pathogenic mixtures compared to individual phages. The cocktail remarkably reduced the viability of naturally contaminated, unidentified in fresh vegetables, demonstrating its effectiveness in targeting diverse bacterial populations. LEC2 and LEC10 recognize different receptors, specifically lipopolysaccharide (LPS) (via WaaC) and OmpC, respectively, supporting their compatibility in a cocktail optimization. Furthermore, genome analysis confirmed the absence of lysogeny-related genes, toxins, and antibiotic resistance genes, reinforcing their suitability as safe biocontrol agents for food applications.
These results demonstrate that LEC2 and LEC10, especially when used as a cocktail, are promising antibacterial agents for controlling contamination in fresh foods. Their complementary host ranges and strong lytic activity support their application in food safety strategies aimed at reducing contamination.
是一种主要的食源性病原体，可导致肠道疾病并引发严重病症。特别是，新鲜农产品中的污染存在重大风险，因为在食用前没有额外的杀菌过程。在本研究中，我们对两种新型噬菌体vB_EcoS_LEC2和vB_EcoS_LEC10进行了表征，并探索了将它们用作噬菌体鸡尾酒来控制新鲜食品中自然存在的污染。
分离出两种噬菌体，并分析了它们的抗菌活性和目标细菌谱。评估了一种双噬菌体鸡尾酒对O157:H7菌株混合物以及市售蔬菜上自然存在的未鉴定的抗菌效果。使用受体缺陷型突变体鉴定噬菌体识别的细菌受体。比较了两种噬菌体的基因组序列，重点关注受体结合蛋白基因。
表征显示两种噬菌体均属于家族，并且在各种温度和pH条件下均稳定。这些噬菌体被证实为严格裂解性的，LEC2和LEC10的潜伏期分别为15分钟和10分钟，每个感染细胞的爆发量分别为22个和189个噬菌体颗粒。LEC2和LEC10表现出不同的抗菌谱，在菌株中各自具有广泛但互补的宿主范围。将两种噬菌体组合成鸡尾酒利用了它们互补的宿主特异性，与单个噬菌体相比，拓宽了整体宿主范围并增强了对致病性混合物的细菌裂解作用。该鸡尾酒显著降低了新鲜蔬菜中自然污染的未鉴定的的活力，证明了其针对不同细菌群体的有效性。LEC2和LEC10分别识别不同的受体，即脂多糖（LPS）（通过WaaC）和OmpC，这支持了它们在鸡尾酒优化中的兼容性。此外，基因组分析证实不存在溶原性相关基因、毒素和抗生素抗性基因，增强了它们作为食品应用安全生物防治剂的适用性。
这些结果表明，LEC2和LEC10，特别是用作鸡尾酒时，是控制新鲜食品中污染的有前景的抗菌剂。它们互补的宿主范围和强大的裂解活性支持它们在旨在减少污染的食品安全策略中的应用。
