貂源绿脓杆菌的分离鉴定及其致病性

为了揭示绿脓杆菌对水貂的致病性，本研究采用细菌分离培养方法、形态学观察、生化试验、药敏试验与16S rDNA测序等技术，对2013年在山东省诸城、文登与临沂采集的43份发病水貂肺组织进行了细菌分离鉴定。结果分离到的5株细菌均为绿脓杆菌（分别命名为F1、F5、F6、F8、F10），分离率为11.6%。所分离的5株绿脓杆菌之间的核酸同源性为 98.9 %～99.7 %； F5、F6、F8、F10与F1在一个大的分支上。用F1株对小鼠与水貂分别进行接种攻毒，建立绿脓杆菌对小鼠与水貂的致病性研究动物模型。F1在小鼠肺部含量较高，半数致死量（LD₅₀）为 1.6×10⁶CFU/mL，对小鼠有较强的致病力；F1对水貂的LD₅₀为3.2×10⁷CFU/mL，接种3.2×10⁸CFU/mL菌液的水貂在接种后的20-44h内全部死亡，其他感染组的水貂仅表现一过性的精神不振、食欲稍有下降，这表明绿脓杆菌对水貂具有一定的致病力。

Identification and pathogenicity test of Pseudomonas aeruginosa from mink

To clarify the pathogenicity of Pseudomonas aeruginosa in mink,bacteria isolation was performed from 43 lung tissue samples which were collected from mink with hemorrhagic pneumonia from Zhucheng, Wendeng and Linyi in 2013. The isolates were identified by morphological observation, physicochemical tests, drug susceptibility tests and 16S rDNA sequencing. The 5 isolates were all Pseudomonas aeruginosa, named F1, F5, F6, F8 and F10, and the isolating rate was only 11.6%. The nucleotide homology of the 5 strains was 98. 9 % -99. 7 % by 16S rDNA sequence homology analysis. Phylogenetic analysis showed that F5、F6、F8、F10 and F1 were clustered in the same branch. F1 was selected as a representative strain for challenge tests on mice and mink, respectively and animal models of pathogenicity of P. aeruginosa to mice and mink were established. Pathogenicity tests showed that the LD50 for mice was 1.6 ×106 CFU/mL and the bacterial content in the lung was higher than in other organs, which indicated that strain F1 had a stronger pathogenicity in mice. The LD50 for minks was 3.2 ×107 CFU/mL and the mink which were inoculated with bacteria solution with 3.2 ×108 CFU/mL were all dead within 20 -44 h,however,the minks in other artificial infection groups only showed transient depression andAnepithymia. It suggests that P. aeruginosa has a certain degree of pathogenicity in mink.