嗜水气单胞菌D102致弱菌株的制备和鉴定

Preparation and Identification of Aeromonas hydrophila Attenuated Strain D102

为研究嗜水气单胞菌D102致弱菌株的制备、OD值变化及其致病性,首先利用细菌在生长过程中毒力不断减弱的特性,对嗜水气单胞菌102正常株进行数次传代培养,得到在血液琼脂平板上没有β-溶血圈的D102致弱株。然后对102正常株和D102致弱株进行OD值测定,发现102正常株在6 h时进入对数生长期,24 h开始进入稳定生长期;而D102致弱株在2 h即开始进入对数生长期,20 h时开始进入稳定生长,对数生长期较正常株提前。鱼体注射0.5 m L的D102致弱株菌液7 d后无发病现象,然后在不发病鱼体上注射强毒性102正常株原菌液。结果表明:80%的鱼正常生长,无发病状态,20%的鱼出现轻微充血后痊愈,D102致弱株对鲤鱼有很好的保护作用;提取不发病鱼的血清进行血清学反应,确定其抗体效价为1∶128。

This experiment is mainly to study the preparation of Aeromonas hydrophila＇ s attenuated strain D102,change of OD value and its pathogenicity. The mechanism is that virulence of bacteria in the growth process is gradually weakening if the strain is passed several times. This experiment take the above measures and get no β-hemolysis on blood agar plates of attenuated strain D102. According to OD value experiment of normal bacterial strain 102 and its attenuated bacteria strain D102,the normal bacterial strain 102 enters logarithmic growth phase in the 6th hour,and stable growth period in the 24 th hour,while attenuated bacteria strain D102 enters logarithmic growth phase in the 2nd hour,and stable growth period in the 20 th hour,which shows that the attenuatedstrain advances than the normal strain in logarithmic growth phase. 0. 5 mL attenuated bacterium strain D102 is injected into a number of fish,and no morbidity phenomenon appears after 7 days.Then high toxic original bacterial liquid is injected into those fish,and the result shows that 80% of the fish is in the state of normal growth and no morbidity status is found,and 20% of the fish recover after mild hyperemia. Serological reaction experiment of normal fish shows that antibody titer is 1 ∶128. Based on these results,strain D102 has a very good protection for carp.