一株尿路致病性大肠杆菌噬菌体的分离鉴定及生物学特性分析

本研究从尿路感染患者尿液样本中分离、鉴定大肠杆菌裂解性噬菌体,对其裂菌活性等生物学特性进行分析,为探索应用噬菌体治疗耐药性尿路致病性大肠杆菌导致的尿路感染奠定基础。利用双层琼脂平板法,从尿液样品中分离、纯化,得到一株能裂解大肠杆菌的噬菌体。通过电镜观察噬菌体形态,测定其裂菌谱、最佳感染复数、一步生长曲线、以及热稳定性、紫外敏感性和氯仿敏感性等生物学特性。结果显示,成功分离、纯化得到一株能高效裂解大肠杆菌的噬菌体vB_EcoS_JA2,该噬菌体可形成圆形、透明、边缘整齐的噬菌斑;电镜观察噬菌体的头部呈六边形,含可收缩性尾部,尾部较长;一步生长曲线显示,该噬菌体的潜伏期为10 min、爆发期为60 min、裂解量高达124 PFU/Cell,其最佳感染复数为0.1;JA2具有较好的热稳定性,且对紫外线具有一定的抵抗力。分离鉴定的噬菌体JA2能裂解致病性大肠杆菌,具有稳定性好,抵抗力强的特点,为应用噬菌体治疗致病性大肠杆菌导致的尿路感染提供了新材料。

ISOLATION, IDENTIFICATION AND ANALYSIS OF BIOLOGICAL CHARACTERISTICS OF PHAGE AGAINST URINARY PATHOGENIC ESCHERCHIA COLI

In recent years, the number of cases of urinary tract infection (UTI) caused by urinary tract pathogenic Escherichia coli (UPEC) has increased. Although antibiotic treatment is effective, a large amount of patients will have recurrent urinary tract infection. Furthermore, in the process of clinical treatment, urinary tract pathogenic E. coli produce a variety of drug resistance, and it is very urgent to develope new efficient antibiotics. The lysate phage of E. coli was isolated and purified from the urine samples of UTI patients. Phage morphology was observed by electron microscope (TEM). The biological characteristics such as MOI, one-step growth curve, thermal stability, UV sensitivity and chloroform sensitivity were determined and it is expected to provide research materials for the application of phage therapy of urinary tract infection caused by pathogenic E. coli. A phage with cleavage of pathogenic E. coli was isolated and identified with the name of vB_EcoS_JA2. It can form round, transparent, edge neat plaque. The head of the phage is hexagonal and has a long tail. The incubation period of phage is 10 min, the outbreak period is 60 min, the burst size is high as 124PFU/infected cell, and the MOI is 0.1. JA2 has good thermal stability and a certain resistance to ultraviolet rays. In this study, an efficient lytic phage vB_EcoS_JA2 against UPEC was identified. The microbiological properties of JA2 suggest that it may be useful for controlling multi-drug resistance bacterial populations, which also provides a new experimental material for the study and therapy of urinary tract infection caused by UPEC.