摘要
目的探讨一株致病大肠杆菌(enteropathogenic Escherichia coli,EPEC)噬菌体EcP1的生物学特性及其对致病大肠杆菌所致脓毒症腹膜炎小鼠的治疗效果。方法从当地三甲医院污水中筛选纯化获得一株致病大肠杆菌噬菌体。通过透射电镜观察其形态、实验室测定最佳感染复数(multiplicity of infection,MOI)及一步生长曲线。使用EcP1治疗致病大肠杆菌所致脓毒症腹膜炎小鼠模型,评估治疗效果。结果透射电镜显示EcP1为肌尾噬菌体,头部呈二十面体,全长约188 nm,尾部长约116 nm,宽约24 nm。MOI为0.1,一步生长曲线显示潜伏期约为20 min,爆发期约为40 min,爆发量约为136。噬菌体单独注射于小鼠未出现不良反应。72 h噬菌体治疗组小鼠存活数量由对照组的0只提高至治疗组的16只(χ^(2)=26.67,P<0.01);噬菌体治疗组小鼠12 h内血液中未检出细菌,对照组菌量达到(1.24±0.43)×10^(5)CFU/ml(t=-6.24,P<0.01);噬菌体治疗组腹腔冲洗液的含菌量低于对照组腹腔冲洗液(t=-4.782,P<0.01)。结论EcP1为裂解性噬菌体,潜伏期较短,裂解能力较强,治疗由致病大肠杆菌所致的脓毒症腹膜炎安全、有效,可作为替代抗生素的生物制剂用于治疗致病大肠杆菌所致的感染性疾病。
Objective To investigate the biological properties of enteropathogenic Escherichia coli(EPEC)phage EcP1,and to determine the therapeutic effect of this phage on mice with septic peritonitis caused by enteropathogenic EPEC.Methods EPEC phage strain in the study was isolated and purified from the effluent of local AAA-rated hospital.The form of phage,measured optimum multiplicity of infection(MOI)in the laboratory and one-step growth curve of the phage were observed by transmission electron microscope.EcP1 was used to treat mice with sepsis peritonitis in the model,and the therapeutic effect was evaluated.Results Transmission electron microscopy showed that EcP1 had myoviridae with an icosahedral head in a full length of approximate 188 nm,the tail with a length of approximate 116 nm and a width of about approximate 24 nm,MOI hit 0.1,the one-step growth curve assay showed that the incubation period of EcP1 hit approximate 20 min,the outbreak period was approximate 40 min,and the outbreak volume hit approximate 136.No adverse effect was found with mice separately injected with phage.The survival rate of mice in phage treatment group increased from zero in control group to 16 mice in treatment group(χ^(2)=26.67,P<0.01);no bacteria were detected in the bloods of mice in the phage treatment group within 12 hours,and the volume of bacteria in control group hit(1.24±0.43)×10^(5)CFU/ml(t=-6.24,P<0.01).The bacterial content of the peritoneal irrigation fluid in phage treatment group was lower than that in control group(t=-4.782,P<0.01).Conclusion EcP1 is a lytic phage strain with a short latency period and strong lytic ability,being effective and safe in the treatment of septic peritonitis induced by EPEC,and it is eligible to be used as biological agent instead of antibiotics to treat infectious diseases caused by EPEC.
作者
陈邬锦
周静茹
张旭华
杨芳
李琴
梁美婷
田婷婷
倪萍
CHEN Wu-jin;ZHOU Jing-ru;ZHANG Xu-hua;YANG Fang;LI Qin;LIANG Mei-ting;TIAN Ting-ting;NI Ping(Morphological Center,School of Basic Medical Sciences,Xinjiang Medical Unwersity,Urumqi 830011,China;不详)
出处
《医学动物防制》
2021年第11期1078-1080,1085,F0003,共5页
Journal of Medical Pest Control
基金
新疆维吾尔自治区自然科学基金面上项目(2021D01C248)。
