Isolation,Identification And Research Of Molecular Epidemiology Of E.coli In The Disease And Dead Duck Embryos In Shandong

There is a lot of reasons causing the death of duck embryos and decreasing of incubation rate during the hatching of eggs. Bacterial infection is a very important factor. Because of its wide spread and the abuse of antibiotics, a variety of pathogenic bacteria drug resistance, bacterial infections have caused severe losses of economy.Since September 2014, Shandong's scale of duck hatcheries embryos' mortality and weak cheeper rate significantly increased. And the type of death to duck embryo is rotten eggs. Initially it is possibly infected by bacterium in a large area. To further explore and study the causes of the duck embryo eggs' death. In this study, the death of duck embryo epidemiology studies of bacteria and molecular characterization of some of its etiology Characteristics on for the interpretation of duck embryo provide a theoretical basis cause of death and prevention of bacterial diseases.This study is divided into five parts1.Large-scale epidemiological survey of bacteria in duck farmThe bacterium in 11 batches of 220 dead duck embryos are isolated and identified through the unbroken eggshell isolation, morphology stain, 16 S r DNA gene testing and other testing methods. There are 175 embryos bacterial infections in a total 187 bacterium, 21 different strains. There are 13 mixed infection. The bacterial infection rate was 79.5%. Also 45 dead embryos. There are 31 unfertilized embryos, 14 allantoic fluid clarification. Escherichia coli 98(52.4%), Salmonella 15(8.6%), Proteus mirabilis 21(11.2%), the other 18 kinds of bacterium, Klebsiella pneumoniae, Pseudomonas aeruginosa are 53 species(27.8%). The results showed that the cause of the duck farm hatchability and weak young rate rise was mainly due to a bacterial infection, and the main pathogen are E. coli, Salmonella, Proteus mirabilis.2.The main pathogens Antibiotic ResistanceUsing Kirby-Bauer method to test the resistance of the isolated and identified 98 duck Escherichia coli, 16 Salmonella duck, duck Source 21 Proteus mirabilis to 18 kinds of antibiotics(cephalothin, tetracycline, kanamycin, norfloxacin, etc.).The results showed that the three main pathogens of 18 kinds of antibiotics exhibit different degrees of resistance. The higher sensibility of several antibiotics in E.coli are gentamicin(82.7%), kanamycin(54.1%), streptomycin(71.4%), nitrofurantoin(84.7%), neomycin(59.2%), polymyxin B(95.9%). The higher sensitivity antibiotic in salmonella are ampicillin(75.0%), cephalothin(75.0%), gentamicin(93.7%), kanamycin(81.2%), streptomycin(100%), tetracycline( 93.7%), ciprofloxacin(93.7%), norfloxacin(93.7%), chloramphenicol(87.5%), cephalexin(75.0%), neomycin(100%), polymyxin B(100%). The higher sensitivity of antibiotic in Proteus mirabilis are cephalosporin thiophene(57.1%), gentamicin(80.9%), streptomycin(71.4%). The study surveys show that streptomycin and gentamicin can be selectively used in the treatment and prevention of the Shandong region ducks hatcheries pathogenic bacterial infections, but also for targeted prevention and control of certain bacterial pathogen infection providing a theoretical basis.3.Duck source E. coli Eric-PCR genotypes identification98 strains of E. coli obviously divided into A, B, C, D, E, F, G, H8 genotypes with the method of unweighted pair group method using averages algorithm, similarity coefficient of 0.7. The main genotype is group B, containing 32 strains of bacterium. Similarity coefficient which was 100% was a total of 14 groups, including several members of the group of up to 11 strains, a minimum of two. B genotype of E. coli in seven batches of dead embryos have appeared, indicating that B genotype of E. coli may be widespread throughout Shandong Province. Different genotypes of E. coli bacteria in different sub-batches have relatively large differences and random, indicating the prevalence of E. coli in different regions is very different and there are geopoliticaldifferences.4.Duck E. coli LPS outer core polysaccharide identificationUsing the method of LPS outer core polysaccharide of PCR genotyping to genotype isolated E.coli. The result is R1(71.4%), R2(6.1%), R3(8.2%), R4(12.2%), K12(2.1%). This result shows the more popular duck E, coli LPS outer core polysaccharide is type R1 in Shandong area. This result provides a theoretical basis for the prevention and treatment of colibacillosis protection.5.The detection and identification of duck E. coli virulence genesUsing virulence genes by multiplex PCR detection method to detect and identify the isolated E. coli of ducks' virulence genes. The result is 33 virulent strains is isolated(33.2%). Among them, fim C, Mat, ibe B, Vat four kinds of genes have very high detection rate. This investigation provides a theoretical basis for long-term monitoring and research of avian pathogenic Escherichia coli.