| 粪肠球菌生长曲线的测定及其对小鼠脑组织的影响 |
| |
| 引用本文： | 王蒙蒙,张莉,李慧,汪骁轩,魏殿华,高静雯,高建鹏,张华雷,齐亚银.粪肠球菌生长曲线的测定及其对小鼠脑组织的影响[J].中国畜牧兽医,2018,45(4):1041-1049. |
| |
| 作者姓名： | 王蒙蒙 张莉 李慧 汪骁轩 魏殿华 高静雯 高建鹏 张华雷 齐亚银 |
| |
| 作者单位： | 石河子大学动物科技学院, 石河子 832000 |
| |
| 基金项目： | 国家自然科学基金项目（31760737）；国家自然科学基金项目（31260610）；兵团现代农业科技攻关与成果转化计划项目（2015AC026） |
| |
| 摘 要： | 为测定致羔羊脑炎粪肠球菌（Enterococcus faecalis）的生长曲线，寻求一种快速而准确的方法测定不同生长时期粪肠球菌数量，并客观评价其毒性强弱及其对小鼠脑组织的影响，试验采用平板菌落计数法和OD-Monitor振荡比浊法（Dλ值法）测定粪肠球菌的生长曲线，探究该菌在合适时间段内的吸光值（D600 nm）与平板菌落计数法测定的活菌数（CFU）的关系。用粪肠球菌感染小鼠，观察记录小鼠的死亡情况，最后采用Karber法计算粪肠球菌感染小鼠的半数致死量（LD50）。用LD50的剂量感染小鼠，及时采集死亡小鼠脑组织，未死亡的小鼠72 h后全部剖杀取脑组织，一部分做涂片染色，制作病理切片，观察病理变化；一部分进行培养，用于PCR方法进行细菌的回收鉴定。结果显示，用两种方法测定此株粪肠球菌的生长曲线基本一致，在2~8 h生长迅速，为对数生长期，8~14 h生长缓慢，为稳定期，14 h之后死亡数增加，进入衰亡期；对12 h粪肠球菌D600 nm与CFU的关系进行探讨，成功建立回归方程：y=20.769x-1.3422，R2=0.997；其感染小鼠的LD50为7.77×1011个活菌。以此剂量感染小鼠，脑组织涂片染色和培养染色，均能看到革兰氏阳性球菌；PCR结果显示，均出现了大小为112 bp的条带。对脑组织进行病理学观察发现该菌可导致脑组织充血、出血、形成微血栓，脑膜充血。通过生长曲线和其D600 nm与CFU关系的建立，可实时监测粪肠球菌数量，为后期更深入研究粪肠球菌穿越血脑屏障的机制奠定重要的理论基础。
|
| 关 键 词： | 粪肠球菌 D&lambda 值法 平板菌落计数法 半数致死量 |
| 收稿时间： | 2017-09-15 |
Study on Growth Curve of Enterococcus faecalis and Its Effect on Brain Tissue of Mice |
| |
| WANG Mengmeng,ZHANG Li,LI Hui,WANG Xiaoxuan,WEI Dianhua,GAO Jingwen,GAO Jianpeng,ZHANG Hualei,QI Yayin.Study on Growth Curve of Enterococcus faecalis and Its Effect on Brain Tissue of Mice[J].China Animal Husbandry & Veterinary Medicine,2018,45(4):1041-1049. |
| |
| Authors: | WANG Mengmeng ZHANG Li LI Hui WANG Xiaoxuan WEI Dianhua GAO Jingwen GAO Jianpeng ZHANG Hualei QI Yayin |
| |
| Institution: | College of Animal Science and Technology, Shihezi University, Shihezi 832000, China |
| |
| Abstract: | The objective of this trial was to determine the growth curve of Enterococcus faecalis that caused encephalitis in lambs and find a rapid and accurate method to determine the number of Enterococcus faecalis at different growth stages,and objectively evaluate its toxicity and effect on the brain tissue of mice.Plate counting method and Dλ value method were used to analyze the growth curve of Enterococcus faecalis. The relationship between the absorbance (D600 nm) and the live bacteria (CFU) measured by plate colony counting method at the appropriate time period was explored.According to the data analysis,mice were infected with Enterococcus faecalis,and the death of mice was recorded.Finally,the Karber method was used to calculate the median lethal dose (LD50) of the mice infected with Enterococcus faecalis.The mice were infected with the dose of LD50,the brain tissues of the dead mice were collected in time and all the mice without death were sacrificed 72 h after infection,and the brain tissues were collected,too.Some of them were stained with smear and the pathological sections were made.Pathological changes were observed.PCR was used to identify bacteria.The results showed that the growth curves of Enterococcus faecalis were basically the same in both methods,the growth of Enterococcus faecalis was rapid at 2 to 8 h for logarithmic growth phase,the growth rate was slow for 8 to 14 h for stable period,the number of deaths increased after 14 h for decline phase.The relationship between D600 nm and CFU of Enterococcus faecalis was studied,and the regression equation was established,y=20.769x-1.3422,R2=0.997.The LD50 for the infection mice was 7.77×1011 live bacteria.With this dose to infect mice,we could see gram-positive cocci in both brain tissue smear and staining.PCR result showed that there was a size of 112 bp band.Morphological observation of the brain tissue of mice found that the bacteria could lead to brain tissue congestion,bleeding,the formation of micro-thrombosis,meningeal congestion.The results of this study revealed that the establishment of the relationship between the growth curve and the D600 nm and CFU could provide a Real-time monitoring of the number of Enterococcus faecalis,and provide an important theoretical basis for further study on the mechanism of Enterococcus faecalis crossing the blood-brain barrier. |
| |
| Keywords: | Enterococcus faecalis Dλ value method flat colony counting method LD50 |
|
| 点击此处可从《中国畜牧兽医》浏览原始摘要信息 |
| 点击此处可从《中国畜牧兽医》下载免费的PDF全文 |
|
