Study On Isolation, Identification Of Cow Mastitis Pathogens And The Pathogenicity Of C.tropicalis

In order to detect the pathogens and incidence of the cows with clinical mastitis of adairy farm in tai’an, pathogens were isolated and identified from the22milk samplescollected at the dairy farm.First，pathogens were separated and identified through selective medium forpreliminary,then further biochemical tests for detail identification of the pathogen. Separatedand identified strains by drug sensitive slips AGAR diffusion method for drug sensitivity test.26SrDNA identification of the yeast isolated and build gene trees. Filter out the strongvirulence strains. Experimental group, each mouse was injected intraperitoneally aboutcontaining1X109CFU/mL of yeast suspension1mL while the control group of mice eachinjection in1mL of normal saline. Observe the animal’s reaction after the injection6h closelyand recorded mice infection situation for30d.5kinds of pathogenic bacteria were isolated for a total of16strains from22milksamples. There were7tropical candida, accounting for43.75%;4strains of staphylococcusaureus, accounting for25.00%;3strains of e. coli,accounting for18.75%;1strain ofsalmonella and streptococcus agalactiae. Staphylococcus aureus and Streptococcusagalactiae had been identified pathogenicity. Drug susceptibility test results showed,Ketoconazole, nystatin and clotrimazolet have good inhibitory effect on yeas; Cefazolin,ceftriaxone, streptomycin, kanamycin, amikacin, ofloxacin, norfloxacin and ciprofloxacinhave good inhibitory effect on the other4kinds of pathogens，while erythromycin andlincomycin is not sensitive or low sensitive to those.Yeast pathogenicity testing results show that,2of the15mice of the experimental groupwere died within15d and there was no death after15d. Liver hemorrhage and necrosis wereseen on the died mice. The lungs have scattered in the bleeder. No obvious lesions in the heart,kidneys and spleen. Yet death in experimental mice have had scattered in the bleeder in part ofthe rat liver and lungs. Swollen spleen obviously than the control group and2mouse ascites.Control group mice were no clinical symptoms and autopsy was also normal. From the routine blood test results we can see that infected with the bacteria is mainly cause the HGB,LYM and RBC, WBC change。Infected in1d,3d,7d, the WBC, LYM and RBC ofexperimental group were higher than the control group obviously. No obvious difference wasfound between the experimental group and control group routine blood results when15d and30d. The experimental group HGB to be higher than that in the control group in1d and3dwhile there was no significant difference after7days. Pathological histology detect on deathmice showed the heart and epicardial congestion, renal bleeding and congestion. The lungbronchioles were surrounded by a small amount of lymphoid infiltrates with severe interstitialpneumonia, accompanied by serous effusion. Liver blood and bleeding was seen,accompanied by granuloma. The spleen has a small amount of eosinophilic lymphoid cellinfiltration. Infection in3d and7d, liver blood and bleeding was also seen. Slight granulardegeneration of the liver cells can be seen. Lung has been infected with interstitialpneumonia. The spleen has a small amount of eosinophilic lymphoid cell infiltration. inaddition to slightly visible lung interstitial pneumonia, other tissues and organs had noobvious histopathological changes when infected15d and30d.Studies have shown that the amateur mastitis is caused by mixed infection of fungi andbacteria. Candida tropicalis as the most important pathogens. Antifungal and antibiotics caninhibit the growth of pathogenic bacteria. Infection Candida tropicalis, early main cause lunginflammation in mice and the rise of the WBC, RBC, LYM content in the blood. However,over time, these symptoms will automatically reduce or disappear.