Study Of The Isolation And Identification Of The Pathog－enic Bacteria And Pathogenesis Of The Bovine Endometritis

Endometritis is one of the major diseases that cause the cow infertility.It ismainly caused by uterine infections of pathogenic microorganisms before or after birt-h.According to statistics,the infertility caused by endometritis accounted for60%to70%of the disease infertility. In abroad, the data indicated that the incidence of the co-w endometritis was about30to40percent. But the incidence was about20to50%inour country.It may lead to the extended calving period,the reduction in milk productio-n,the increase in the rate of death and cost of treatment and the waste of milk during t-herapy for endometriosis cows.However,the kinds and proportion of various pathoge-nic bacteria separated from the uterine contents of the endometritis cow in different r-egions were not the same.This study stated the separation and identification of bacter-ia from endometritis cow of a dairy in Ping Dingshan city and uterine contents of Jia-xian red cattle、drug sensitivity test and pathogenicity test of Kunming mice.Based onthe level of the isolation rate、drug resistance of the sample bacterial combinatiing wit-h the pathogenicity test results,five bacterial were selected to undergo the copy of thecase model of the Kunming mice endometritis.We observed the uterus tissues and thei-r cell damage by modeling the pathological section of the mice uterine tissues using t-ransmission electron microscope to reveal the pathogenesis of endometritis.1.Isolation and identification of bacteria separated from the uterine contents from Jiax-ian red cattles and cows endometritis:18kinds (52strains)bacteria in total were sepa-rated and cultured、purified and identified from uterine contents of29diagnosed clini-cal cows endometritis of a dairy farm,mainly of which were Bacillus cereus, Moraxel-la osloensis, Escherichia coli, Streptococcus, Bacillus thuringiensis.In the meantim-e,we collected the uterine contents samples of21Jiaxian red cattles that had no clinic-al symptoms of endometritis,and then separated, purified and identified.A total of14kinds(43strains) bacteria were isolated,which were mainly Bacillus cereus, Escherichi-a coli,Chryseobacterium indologenes,Chryseomonas luteola,Moraxella osloensis.10kinds of bacteria were consistent with those isolated from the endometritis cows in the14kinds of bacteria isolated.In addition,from the Gram stain results of the bacteria iso-lated from the uterus contents of Jiaxian red cattles,Gram-positive bacteria were23str-ains(53.5%),Gram-negative bacteria were20strains(46.5%),both were consistent w-ith endometritis cows.2.Drug sensitivity test: in order to study separated bacterial sensitivity to drugs,we selected24kinds of drugs as the standards in commonly used drugs andmeasured the sensitivity of bacteria isolated to24kinds of drugs with microco-ntent broth dilution method.18kinds of bacteria isolated from cow samples we-re sensitive to ciprofloxacin, enrofloxacin, florfenicol and chloramphenicol.Stap--hylococcus epidermidis produced resistance to tetracycline, oxytetracycline andchlortetracycline but sensitive to doxycycline,which suggested that the bacteriahad not generated completely cross-resistance to tetracyclines.All bacteria had ahigher resistance to amoxicillin, ampicillin.Or Escherichia coli, Staphylococcus e pidermidis, Kocuria roseus, Corynebacterium, Chryseobacterium meningosepticu-m were all resistance to-lactamase inhibitor (clavulanic acid).14kinds of bac-teria separated from the Jiaxian red cattle samples were more sensitive to Cipr-ofloxacin, enrofloxacin, tetracycline, doxycycline, chloramphenicol, flofenicol,tilm-icosin.All the bacteria except for Streptococcus uberis (intermediary), had a hi--gh resistance to amoxicillin, ampicillin.3.Pathogenicity test: Pathogenicity test was conducted for the bacteria isolated from th-e endometritis cows and uterine contents of Jiaxian red cattle.Fresh pure culture colle-ction of bacteria at0.5mL was inoculated to abdominal cavity of Kunming mice, andthe death situation of the mice were observed and recorded then. The results showed t-hat: Bacillus cereus,Micrococcus luteus,Staphylococcus epidermidis, Escherichia col-i separated from the Jiaxian samples and Escherichia coli, Chryseobacterium mening-osepticum, Streptococcus dysgalactiae, Bacillus thuringiensis, Chryseobacterium ind-ologenes isolated from the cows samples were all able to cause the Kunming mice todeath within2d after abdominal tapping bacteria culture solution,especially the Esche-richia coli isolated from the Jiaxian samples could lead Kunming mice to death withi-n2~3h of after abdominal tapping bacteria culture solution.4. Establishment of endometritis cases mode of Kunming mice: according to the levelof the separation rate, strength of resistance and pathogenicity of bacteria in the sampl-e, we selected five bacteria to establish the endometritis cases model of Kunming mic-e. We should put the mice to death after having inoculated bacteria for3d,and then ta-ke out the uterine to isolate bacteria. The results showed that: the inoculated bacteriacould be isolated from the uterine of each model group, and also be found in the splee-n and liver.The bacteria were not isolated from the physiological saline control groupand blank control group. The result of uterine tissues biopsy and electron microscopyshowed that:①HE staining results of each model mice group revealed the degenerati-on, necrosis, loss of the epithelial cells of the uterine mucosa, capillary congestion, la-rge number of neutrophils and lymphocytes infiltration in the endometrial and myom-etrial, as well as arrangement relaxation、loose and rupture of muscle fibers,in somemodel groups.②The observation for ultrastructural structure of the uterine tissues ofeach model group showed that a large number of vacuolar structures in the cytoplas-m、nuclear membrane and cytoplasm fissures、intranuclear vacuoles and apoptotic bo-dies can be seen in the majority of cells.③HE staining results of physiological salinecontrol group and blank control group, and ultrastructural observation results of the tr-ansmission electron microscopy (TEM) showed that the structure of uterine tissue lay-ers were close to normal,cell structure in the tissues also maintained good integrity.According to the results of the above,we can make preliminary judgment that Bacilluscereus, Escherichia coli from the Jiaxian red cattle samples and Bacillus cereus, Esch-erichia coli and Staphylococcus epidermidis from the endometritis cows samples cancause acute endometritis of Kunming mice. The follow-up work like stable model of t-he endometritis of Kunming mice, and clinical treatment trials, still needs further stu-dy.