The Finding Of Lamb Encephalitis Induced By Enterococcus And Studies On Its Pathogenic Characteristics And Diagnosis Method

Enterococcus are usually studied as useful microorganism bcause of commensals of the intestinal tract of humans and animals but have emerged in recent decades as a major cause of nosocomial infections Enterococcus infections represent the second most common cause of bacteraemia and endocarditis after Staphylococcus in US hospitals from NISS Survey. Recently, there is a infectious diseases of 20-40 day old lamb which main characteristics are neurological symptoms and the septicemia in large-scale farms for the sheep of Xinjiang Production and Construction Corps in the same season. Lamb mortality is about 20%. It is identified as lamb encephalitis induced by Enterococusi through the isolation of bacteria and regression test. It is a new infectious diseases of lamb. A series of research n pathogen characteristics and diagnostic method are done in order to provide scientific data for pathogenic mechanism and control of the disease effectively about Enterococcus.1 The Finding of Lamb Encephalitis Infected by Enterococcus Isolated and Identified 11 Enterococcus isolated from lamb encephalitis in partial breeding farm of Xinjiang Production and Construction Corps are identified by a series of tests. They belong to serum type D,G and unidentifiable type by Latex. They can led to mouse and partial guinea pigs or rabbits dead. The 11 bacterum have resistance for streptomycin,gentamicin, erythromycin and partial resistance to norfloxacin, penicillin, tetracycline, but sensitivity to nitrofurantoin, rifampin, chloramphenicol and vancomycin.2 Development of ELISA to Detecte the Antibody for Enterococcus Inducing Lamb Encephalitis and Preliminary Application A ELISA are developed by phalanx titration with coating antigen of Enterococcus faecalis cracked by ultrasonic. It is more 25-100 times sensitive than micro-agglutination test through some positive serum for Enterococcus, and It has the more specific characteristic, easy or quick to operate. 2 serum in 50 adult sheep serum are positive in adult sheep serum detected.3 Development of PCR to Detect Antigen for Enterococcus Inducing Iamb Encephalitis and Preliminary Application A PCR are developed base of Conservative gene tuf gene to detect Enterococcus. The optimal reaction conditions is that nuclease refolding temperature is 55℃, Mg²⁺ Concentration is 2.5um and reaction mode is 95℃5min, 94℃30s, 55℃30s, 72℃30s, 35 cycle, 72℃10 min. The sensitivity of this mathod is 10fg. The other 10 Enterococcus, the tissue from lamb and mouse infected by Enterococcus faecalis can be amplified special electrophoresis bands about 112bp and no any bands can be amplified in S.equi s, bsp.equi, Streptococcus G,Streptococcus A,S.aureus, L.monocytogenes,M.ovipneumoniae, Br.ovis and Enterococcus faecalis inducing lamb encephalitis.4 A Study on the Detection of Enterococcus faecalis Inducing Lamb Encephalitis and Antigen Location by Immunoenzymatic Histochemistry An indirect Immunoenzymatic Histochemistry is developed to detect the distribution of Enterococcus faecalis in mouse artificial infected. The result indicated that positive particles of Enterococcus faecaIis can be detected in liver in 4h, in kidney and heart at 14h, in esophagus at 18h, in encephalon and in all tissues except for spleen of mouse infeted at 24h.5 The research of Molecular epidemiology for Enterococcus inducing lamb encephalitis 9 virulence factor genes(ace,efaA,cylA, gelE, asaland asa373,esp,EF0591 and EF3314)in 11 Enterococcus inducing lamb encephalitis are detected. The results indicated that there is 7viru-lence factor genes in 5 bacteria (5/11),6 virulence factor genes in 3 bacteria (3/11), 1viru-lence factor gene in 1 bacteria (1/11),no virulence factor genes 2 bacteria (2/11).6 Gene Cloning and Sequence Analysis of Virulence Factor Genes in Enterococeus facealis Inducing Lamb Encephalitis 8 virulence factor genes (ace, efa,cylA,gelE, asa1, esp, EF0591, EF3314) segments amplyfied are cloned in pMD19-T and the positive clone are going to determin the nucleotide Sequence, the results indicated that the homology is 99.3%,99.56%,99.3%,97.85%,96.64%,99.9%,99.29% and 98.11% between the Enterococcus faecalis from lamb encephalitis and corresponding sequence from GeneBank.7 A Comparative Study of Biological Characteristics of Enterococci from Different Sources of Lamb The study on cultural characteristics, biochemical characteristics, hemo- lytic properties, drug sensitivity and the types, distribution of virulence factor gene of Enterococcus inducing lamb encephalitis and normal flora indecate that basic biochemical chara- cteristics of enterococci from two different sources of lamb are consistent. Pathogens have resistance for Streptomycin, gentamicin and erythromycin, one bacterial from normal flora have resistance for tetracycline, erythromycin, streptomycin, esp,cylA,asal,ace,efa,EF0591 and EF3314 can be detected in 5/11 from Enterococcus inducing lamb encephalitis. gelE and EF3314 can be detected in 3/30 from normal flora and gelE,EF3314 and asal can be detected in 1/30 from normal flora. The homology of 3 gene sequence is more than 95% between GeneBank and bacteria from normal flora, the corresponding sequence is more than 96% with patho-genic strains, pathogens can cause the death of mice, whereas the Enterococci from normal flora can not cause the death of mice.8 A study on distribution and pathological changes in artificial infectious mice disease model forEnterococcus faecalis inducing Lamb encephalitis A study on 135 mouse infec ted by Enterococcus faecalis inducing Lamb encephalitis with different ways indicates that intraperitoneal injection is the best way, subcutaneous implant is second way and nasal inhal-ation can not cause infectious. LD₅₀ of the bacteria is9.3×10¹⁰CFU. Enterococcus faecalis DNA can be detected in encephalon, liver and blood spleen in artificial infectious mouse at 2h. Enterococcus faecalis and its DNA can be detected in the tissues at 6h. Signifiant histopatho-logical changes are observed during 4-6h and the changes of ultrastructural organization are observed at 4h.