Isolation And Identification And Parts Of Biological Characteristics Of Pasteurella Multocida Inducing Pneumonia Of Calf

Pasteurella mutocida was an important pathogen of hemorraghic septicemia in cattle.It was endemic or diverging. HS charactered by significant form of hemorrhage, septicaemic,,hyperthermy,pneumonia or acute gastroenteritis predominantly in cattle. In 2007,The sick calf with age between one to nine weeks was characterized by fever, dyspnea and pathological changes in lung,part of which have diarrhea and about ninety calf died of pneumonia in six pastures of dairy cow in Xinjiang shihezi.In order to determine the etiology of sick calves, preventing and to control the spread of the disease effectively. We made a description of isolated bacteria on the basis of morphological features, physiologeical,biochemical characteristic,molecule biology, animal infection assay,drug sensitivity test and detection of virulence factor.Result showed that:The four isolates were Gram-negative rod bacteria.Biochemical characteristics and morphological features of this isolated bacteria were identified uniformly with Pasteurella mutocida which was reported, causing of HS.The designed of primer refer to species—specific kmtl gene and serogroup—specific hyaD-hyaC, bcbD, dcbF, ecbJ and fcbD gene and amplificated by PCR.500bp kmtl gene fragement and 1000bp hyaD-hyaC gene fragemen were amplified respectively with the genome of each isolate as template.PCR products was contrasted by BLAST. Results indicated that the four bacterial isolates belong to capsular-serotype A of Pasteurella mutocida.By injecting isolates pure culture to Mus musculus albus and rabbit,the experiment animals were all died after 72h.The pathogenicity test showed the isolate had fort pathogenicity to experiment animal and aim bacteria was obtained from the infected Mus musculus albus and rabbit.The results of drug sensitivity test showed that isolated bacteria was sensitive to GEN, OFX,but resistantedto AMP.Primers were designed and amplificated by PCR to detected the virulence factor of four isolates. Comparison of sequencing results of iron acquisition-related factors gene tbpA sequence and type four fimbriae gene ptfA sequence of Pasteurella mutocida by GenBank showed that only ptfA gene can be detection.Pathologic histology observation showed that the affection mainly occurred on pulmones Telangiectasis on alveolar wall, serous edema of pulmonary alveoli, fibrin exudation on alveolar space,small amounts neutrophilic granulocyte and akaryocyte were observed.But other organ only had light hemorrhage.This was the first reported capsular-serotype A of Pasteurella mutocida Inducing Pneumonia of Calf in Xingjiang. This paper systematacially studied some of biological chatacteristics of this isolated Pasteurella mutocida.