Slection Of Clinical Bovine Mastitis Pathobacteria And Study On Pathogenicity To Mice (Ⅱ)

The clinical bovine mastitis is a kind of infectious disease, mostly caused by lots of pathogenic microorganism, shows obvious clinical symptom in udder and milk. Mastitis is caused by lots of factors,but the infection of pathogeny is important. In this experiment, 109 pathogenic microorganisms were isolated from 139 milk samples of 48 cows from 2 cattle farms and 5 cultivation villages in Huhhot region.75 of 109 pathogenic microorganisms were identified by biochemical methods. Results: 22 Staphtococcus aureus (19/75),Staphtococcus epidermis (15/75),Staphtococcus saprophyte (1/75),Streptococcus agalactiae (1/75),Streptococcus uberis (4/75),Streptococcus lactis(1/75),Streptococcus bovis(12/75), Streptococcus faecalis(1/75),Streptococcus diapyesis(6/75),Streptococcus dysgalactiae(6/75),Escherichia coli (1/75),Klebsiella sp. (1/75),Proteus sp. (9/75),Shigella Chalmers(2/75). Staphtococcus aureus is a primary infectious pathogenic. According to heamolyticus and biochemistry characteristics, selected 11 isolated pathogenic microorganism and diluted by disinfectant physiological brine.20±1㎏ healthy mice were respectively injected by abdomen route (0.5ml per mouse) with bacterial suspensive liquld 9 hundred million per milliliter, observed the development of state of an illness and the clinical manifestation of the mice . Furthermore, the mice were killed and their material was drew after 7 days; Inspected histopathologic changes. Selected the livers of dissected mice, isolated pathogenic strain again, selected pathogenic microorganism. It shows there appeared death cases even infected by Staphtococcus aureus strain, Proteus sp.strain, or Streptococcus uberis strain. The cases infected by Staphtococcus aureus died quickly, and had obviouse changes in histopathology, there were lots of necrosis focuses in cortex and medulla of kidney ,which were various in size; liver had degeneration changes; spleenic pulp is abound with neutrophilic leukocyte; myofibrosis cordis; small vessels dilatation of thymus gland, medulla have slight lymphocyte necrosis, which display phyknosis. A pancreatic gland, salivary gland, small intestine, esophagus had different damages; Streptococcus uberis is stronger than others in pathopoiesis and death rate .In addition, according to cultural character, 35 pathogenyes were selected to test the sensitive to 18 kinds of antibiotic. The result indicate that cefradine, cafalotin, ciprofloxacin, rifampicin, norfloxaxin and ofloxacin are more sensitive, above 60℅, but most strains is tolerant to streptomycin, erythromycin, tetracycline, oxacillin, ampicillin, selcetrin ,above 60℅.