The Study Of Isolation And Identification Of Cow Footrot Pathogenic Bacterium And Biological Characteristics To The Pathogens

Footrot which arises commonly the cow, the sheep, the deer and other counter-hay animal andhas higher the disease incidence is a kind of harmful serious infectious disease. In the counter-hayanimal's hoof disease, it causes serious harm. Bacteroides nodosus and Fusobacteriumnecrophorum are the major pathogenic bacteria of Footrot. The pathopoiesis mechanism ofBacteroides nodosus is due to the bacterial pilus and protease, and the pathopoiesis mechanism ofFusobacterium necrophorum is due to leukocytotoxin, endotoxin, hemolysin, prothrombin andvarious kinds of proteases. Except for two bacteria, other bacteria also have subsidiary function inFootrot's pathopoiesis mechanism, so exists of Bacteroides nodosus and Fusobacteriumnecrophorum which are detected in the examples will be the main identification evidence ofFootrot.The experiment is the isolating culture and identification of pathogenic bacteria of 11 shares ofcows Footrot examples which are gathered in the Heilongjiang Province. All examples of 4 sharesof cow's bad hooves tissues which are from the green farm and 3 shares of cow's hooves thickjuices which come from Nine Three farms are also separated accurately from the pathogenicFusobacterium necrophorum, but aren't observed and separated from Bacteroides nodosus.Meanwhile, the chaincoccus, Escherichia coil,salmonella,the excrement Bacterium flexuosus,Corynebacterium pyogenes,the shuttle bacterium, the yeast fungus and the different cocci and soon are separated accurately from these examples. Especially Corynebacterium pyogenes and shuttlebacteria are helper factors of Footrot; The chain coccus, Escherichia coil, the different cocci and soon are the common bacteria in the environment.Through the isolating culture of pathogenic bacteria of Footrot examples, the aim is that thehorse frozen hematolysis and the oxygenium-phobe agar solid medium which are suitable forseparation of pathogenic bacteria can be screened; sulphur glycollate and Fusobacteriumnecrophorum fluid medium which are suitable for proliferation of pathogenic bacteria can bescreened; and desiccator cultural method which is suitable for optimum cultivation condition ofpathogenic bacteria is also found. Simultaneously passing through the biochemical identificationand confirmation of the PCR detection experiment, Fusobacterium necrophorum is main pathogenic bacteria in the examples gathered, however,Bacteroides nodosus is inexistence.The result of susceptibility test of separating Fusobacterium necrophorum indicates that thepenicillins, cephalosporins and Clindamycin have the best depressant effect with regard toFusobacterium necrophorum; The erythrocin, and the Chinese materia medica group prescriptionⅠare moderately sensitive to Fusobacterium necrophorum; kanamycin, gentamycin and vancomycinand so on are drug fast toward Fusobacterium necrophorum..In the experiment of the conservationcondition of Fusobacterium necrophorum the result of the experiment indicated that Fusobacteriumnecrophorum can completely survive 2 weeks in the 4℃condition, 3 months in -20℃conditionand above a year in -70℃condition. In the experiment of growth rule determination ofFusobacterium necrophorum, the result of the experiment indicated that the logarithmic phase ofgrowth of Fusobacterium necrophorum is between20～38h, and the stationary phases of growth ofFusobacterium necrophorum is after 34～38h. In the pathogenicity experiment of experimentalanimal with separating Fusobacterium necrophorum, it may cause morbidity and death ofexperimental mice and rabbits. Simultaneously Fusobacterium necrophorum are shownβtypehaemolysis in the reculture process. The result of the experiment indicated that Fusobacteriumnecrophorum of separation and purification have the pathogenicity.According to above the result analysis of the experiments, it indicates that the main pathogenicbacteria of cow footrot of the partial farms of Heilongjiang Province is Fusobacteriumnecrophorum.. Simultaneously there are the massive other bacteria without Bacteroides nodosus.The death rate of footrot is lower, but it can lead to enormous economic loss. The experiment isabout the study of separation identification and biological characteristics of pathogenic bacteria ofcow footrot in order to scientically guide clinical medication, provide scientical evidence withcuring footrot and necessary experiment foundation with deeply carrying on the study of pathogenicbacteria of footrot.