Li Pei, Li Zhuojun, Peng Wan, Li Xiaoyue, Guo Genglin, Chen Long, Pang Xiaoxiao, Chen Mianmian, Li Juan, Wei Yinglu, Zheng Yishan, Zhang Wei
Department of Intensive Care Unit, The Second Hospital of Nanjing, affiliated with Nanjing University of Chinese Medicine, 210003 Nanjing, China; Ministry of Education Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Key Laboratory of Animal Bacteriology, Ministry of Agriculture, 210095 Nanjing, China.
Ministry of Education Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Key Laboratory of Animal Bacteriology, Ministry of Agriculture, 210095 Nanjing, China.
J Dairy Sci. 2025 Jul;108(7):6788-6802. doi: 10.3168/jds.2024-25895. Epub 2025 Apr 28.
The nutrient-rich composition of milk creates an optimal environment for bacterial proliferation, making the inhibition of microbial growth essential for maintaining dairy product quality and ensuring consumer safety. Klebsiella pneumoniae is an important contaminant of milk and a leading cause of bovine mastitis. Although the increasingly serious antibiotic resistance has led to a renewed interest in phage therapy, research on antimicrobial potential of Klebsiella phages in milk remains scarce. The K5 serotype of K. pneumoniae is a major concern due to its high virulence and prevalence in dairy farming operations. Despite its clinical and economic importance, the availability of phages specifically targeting this serotype remains substantially limited. Here, we successfully isolated and sequenced 2 K1-specific Klebsiella phages, P284 and P287, and one K5-specific Klebsiella phage P252. We identified the receptor-binding proteins with depolymerization activity in these phages. The phage library against K5 K. pneumoniae was enriched by phage genome modification. Specifically, we replaced the receptor-binding protein of K1-specific phage P284 with that of K5-specific phage P252, resulting in the generation of recombinant phages T and F, which exhibit specific lytic activity against K5 K. pneumoniae. Compared with phage P252, recombinant phages T and F exhibited better and more prolonged antibacterial potential in planktonic assay. In addition, all these K5-specific phages could significantly inhibit bacterial growth and reduce bacterial populations in milk at 4°C and 38°C. In summary, this study provided K5-specific phages with potential application in managing K. pneumoniae contamination and infection in the dairy industry.
牛奶中丰富的营养成分营造了细菌增殖的最佳环境,因此抑制微生物生长对于维持乳制品质量和确保消费者安全至关重要。肺炎克雷伯菌是牛奶的一种重要污染物,也是牛乳腺炎的主要病因。尽管抗生素耐药性日益严重,引发了人们对噬菌体疗法的新兴趣,但关于牛奶中肺炎克雷伯菌噬菌体抗菌潜力的研究仍然很少。肺炎克雷伯菌的K5血清型因其高毒力和在奶牛养殖中的高流行率而备受关注。尽管其具有临床和经济重要性,但专门针对该血清型的噬菌体仍然非常有限。在此,我们成功分离并测序了2株K1特异性肺炎克雷伯菌噬菌体P284和P287,以及1株K5特异性肺炎克雷伯菌噬菌体P252。我们鉴定了这些噬菌体中具有解聚活性的受体结合蛋白。通过噬菌体基因组改造富集了针对K5肺炎克雷伯菌的噬菌体文库。具体而言,我们用K5特异性噬菌体P252的受体结合蛋白替换了K1特异性噬菌体P284的受体结合蛋白,从而产生了重组噬菌体T和F,它们对K5肺炎克雷伯菌具有特异性裂解活性。与噬菌体P252相比,重组噬菌体T和F在浮游试验中表现出更好、更持久的抗菌潜力。此外,所有这些K5特异性噬菌体在4°C和38°C下均能显著抑制牛奶中的细菌生长并减少细菌数量。总之,本研究提供了具有在乳制品行业管理肺炎克雷伯菌污染和感染潜在应用价值的K5特异性噬菌体。