Isolation And Identification Of Trueperalla Pyogenes From Cow Mastitis And Investigation Of Its Biological Characcteristics

An infectious disease, mainly characterized by reduction in the breast milk secretion, loss of appetite, breast tenderness, occurred in a dairy farm in Xianyang Shannxi province, were identified as clinical mastitis. For the diagnosis and prevention of the occurrence of disease, by means of isolation and purification of bacteria, morphological observation, biochemical test and drug sensitivity test in vitro, we identified a pathogenic bacteria named HNYM. The results were summarized in the following points:1. A strain of bacteria named HNYM was isolated from diseased cow milk. The strain grow well on blood agar with β hemolytic phenomena. Colonies were tiny, needle-shaped, flat, neat edge, white, opacity and dry, stain showed positive and bacilli.2. Making carbohydrate fermentation test with the bacterial, it could ferment glucose, maltose, fructose, lactose, D-fructose, mushroom sugar, rhamnose, D-xylose, arabinose, synanthrin to product acid. M.R, V-P test, contact enzyme test were negative, suspected it was trueperalla pyogenes. Sensitive to disinfectant and beta lactam antibiotics, resistant to sulfa drugs.3. The 16 SrRNA sequence was highly homology with the trueperalla pyogenes, between 92% to 99%. The analysis results of phylogenetic tree was showed that the HNYM strains at the same type with trueperalla pyogenes, The cow was finally diagnosed as infection of trueperalla pyogenes.4. Mice were injected with different volume of bacterial, autopsy was found that heart, liver, lungs and other tissues had significant pathological changes. By intramuscular injection of the mice with different volume of bacterial and found that the leg muscles was festered and necrosised, hind legs was paralyzed. The control groups were alive. The experimental results showed that the HNYM strains of trueperalla pyogenes were pathogenic to mice and the main pathogenic factor is external toxin.In conclusion, the research separated the HNYM strain and identified it as trueperalla pyogenes, drug resistance is not strong but with high pathogenicity.