To Cause The Lamb Encephalitis Separation Identification Of Enterococcus Faecalis

At midmonth of December in2011, a herd of hybridization Small Tail Han sheep suffered from an illness called encephalitis which is as the main symptoms of the disease on a scale sheep farm in Xinjiang Wusu area and about30one month old sheep died. The disease not only caused economic losses to the sheep field greatly, but also pose a threat to the surrounding sheep farm. To determine the etiology of lamb encephalitis the farm led to, based on the epidemiological, clinical examination, and pathological anatomy, we have three dead lamb brain, liver, spleen, lymph node tissue pathogen isolated and identificated. And we take the ways of patient material smear staining microscopy, isolated strainbiochemical test, PCR test isolates,16S rRNA sequence analysis, phylogenetic tree analysis, drug sensitivity, pathogenicity in mice and mouse brain tissue pathological observation to continue the study. The results are as follows:1、Isolated bectrial strains’ staining, cultural characteristics and biochemical characteristics are basically the same as isolates’ from Xinjiang area. They all showed a strong tolerance to high temperature, low temperature, high salt and alkali, and had obvious alpha or beta hemolytic, and can grow in bile with high concentrations, which were in full compliance with the biological characteristics of enterococci;2、We compared the strains of WS1, WS2, WS3, WS4, WS5with their homology by Application of DNAman software, and the homology with Enterococcus faecalis were99.2%,99%,98.5%,98.5%,98.8%in the GenBank database. The molecular phylogenetic tree(N-J method) analysed by MEGA4.0software showed that the5strains were the ones most closed to Enterococcus faecalis individual. The results show that, the death of lamb suffered from encephalitis is caused by Enterococcus faecalis.3、The result of drug sensitivity test showed that Isolates had strong resistance.to gentamicin, erythromycin, and clindamycin, showed extreme sensitivity to nitrofurantoin,and were sensitive to penicillin, ampicillin, ciprofloxacin;4、The isolated5strains of bacteria were prepared into a certain unit of bacterial suspension. We observed the pathogenicity of mice by intraperitoneal injection of suspension prepared before. The results showed that symptoms infected mice were back hair put up, circling, and standing uncertainties, and death rate reached75%within24hours. Bacteria were recovered from the dead mice’s brain tissues. And we conducted the biochemical test and PCR test and found that the isolates was Enterococcus faecalis, which had strong pathogenicity to mice.5、In the observation of pathological section of brain tissue, we found that one or more regional abscess had formed and local tissue began to dissolve or liquefy. The organizational structure became vague, blood vessels was congested and nerve cell periphery had large gap.The phenomenon further illustrates the strains caused mice brain tissues’ lesions and further validated lamb symptoms of encephalitis.