嗜麦芽窄食单胞菌裂解性噬菌体TS-10的特性及其对细菌生物膜作用研究

Characterizations of Stenotrophomonas maltophilia lytic phage TS-1o and its effect on bacterial biofilm

目的 从湖水中分离特异性针对嗜麦芽窄食单胞菌的噬菌体,分析其生物学特性,并检测其对细菌生物膜的裂解作用。方法 通过双层琼脂平板法对噬菌体进行分离并纯化,用透射电镜观察其形态,并测定其最佳感染复数、一步生长曲线、温度及酸碱稳定性。提取基因组DNA进行测序分析,采用生物膜形成抑制试验和裂解试验观察噬菌体对嗜麦芽菌生物膜的影响。结果 嗜麦芽窄食单胞菌噬菌体TS-10呈现出典型的蝌蚪状外形,头部为正二十面体结构,TS-10头部直径为110~115 nm,尾部长120~125 nm。TS-10最佳感染复数为0.01,潜伏期为15 min,裂解期为65 min。TS-10可在60℃、pH 4~11的环境中存活。TS-10属有尾噬菌体目、肌尾噬菌体科,其基因组大小为4 2391 bp,含53个开放阅读框,与窄食单胞菌属噬菌体亲缘关系较近。生物膜形成抑制和裂解试验显示,TS-10能抑制嗜麦芽菌生物膜的形成且有一定的裂解作用,其中抑制试验菌液A值较对照组减少88.5%,裂解试验菌液A值较对照组减少35%(P<0.05或P<0.01)。结论 噬菌体TS-10裂解性强、特异性高且稳定,可望用于多重耐药嗜麦芽窄食单胞菌感染的治疗。

Objective Isolation of phage specifically targeting S.maltophilia from lake water,analyzing its biological characteristics,and examining its lytic activity against bacterial biofilms.MethodsThe phages were isolated and purified using the double-layer agar plate method.The morphology of the phages was observed under transmission electron microscopy,and their optimal infective titer,one-step growth curve,temperature dependence,and pH stability were determined.Genomic DNA was extracted for sequencing analysis.The inhibitory assay for biofilm formation and the lytic assay were conducted to observe the impact of the bacteriophages on S.maltophilia biofilm.Results The S.maltophilia phage TS-10 exhibits a typical tadpole-shaped appearance,with a head that exhibits a regular icosahedral structure.The diameter of the TS-10 head ranges from 110 to 115 nm,while the tail measures 120 to 125 nm in length.The optimal infective titer of TS-10 is 0.01,with a latent period of 15 minutes and a burst period of 65 minutes.TS-10 demonstrates survival capabilities within a temperature range of 60 C and pH levels ranging from 4 to 1l.TS-1o belongs to the Caudovirales order and Myoviridae family,with a genome size of 42391 bp that contains 53 open reading frames.It shows a close phylogenetic relationship with bacteriophages of the narrow-feeding monococcus genus.In biofilm inhibition and lytic assays,TS-1o is capable of inhibiting biofilm formation in maltophilic monococcus and exhibits significant lytic activity.The biofilm inhibition assay shows a reduction of 88.5%in value for test group A compared to the control group,while the lytic assay shows a decrease of 35%in value for test group A compared to the control group(P<0.05 or P<0.01).Conclusion Bacteriophage TS-10 exhibits strong lytic activity,high specificity,and stability,making it a promising candidate for the treatment of multi-drug resistant infections caused by S.maltophilia.