PCP Serological Investigation And Study Of Isolation And Biological Characteristics Of APP In Anhui

Porcine contagious pleuropneumonia is a highly contagious respiratory disease of pigs,which caused by Actinobacillus pleuropneumoniae(APP).In 1990,Yang Xufu first confirmed the existing of the disease in our country,huge economic losses was caused to our pork production.In order to investigate the prevalence PCP,to improve the detection rate of subclinical APP infection and bacterial isolation rate of APP,and to study the biochemical characteristics and gene type in Anhui area,this test was carried out from the following aspects.Apx1V-ELISA kit was used to detect the APP antibody of 1288 serum samples,respectively from the stage of growth,season,geographic region,pig breeding scale to analyze the epidemic characteristics,and compared with other areas in Anhui province the overall PCP infection.The results showed that,the total antibody positive rate of APP infection was 26.40%(340/1288),the antibody positive rate of sows,replacement gilt and boars was 45.47%,and higher than that of suckling piglets(28.02%),nursery pigs(6.16%)and growing pigs(7.20%).The antibody positive rate of summer(41.42%)was higher than that of spring(29.75%),autumn(26.35%),winter(19.26%).The antibody positive rate of South region of Wannan area(13.77%)was lower than that of Huaibei area(30.73%)and Jianghuai area(28.57%).The antibody positive rate of middle size farm(47.16%)was higher than that of large size farms(19.28%),small pig farms and backyard farmers(23.15%).The epidemiological characteristics of PCP of Anhui province provide scientific basis for the development of effective prevention and control measures.Comparison the sensitivity and specificity of omlA-PCR,dsbE-PCR and Apx?A-PC R,and those three PCR methods were used to detect the nucleic acid of APP for total 135 nasal swabs of sows.The results show that,the minimum detection limit of three PCR was 102CFU,and have high specificity to other bacteria.The nucleic acid detection rate of dsbE-PCR method(23.7%)was significantly higher than that of omlA-PCR(8.1%)and ApxIVA-PCR(14.8%),and the coincidence rate was 84.4%?91.1%and 93.3%.This study laid foundation for the improvement of reference molecular method of subclinical infection of APP detection.At the same time,the use of antibiotics,NAD and serum in mPPLO,TSA,CA and BA four kinds of selective separation of a total of 135 nasal swabs of sows,and compare the isolate rate of four medium.The results show that,The APP isolation rate of mPPLO(11.9%)was significantly higher than that of TSA(0.7%),CA(5.2%)and BA(2.2%),four with higher rate,respectively 88.9%?93.3%?90.37%?95.6%?98.5%and 97%.This study provided theoretical reference for the optimization of culture methods for APP isolated from pig in the nasal cavity.By bacteriological tests,to study the biochemical characteristics of isolated and reference strains of APP.The results show that,APP belongs to gram negative,with pleomorphic cells,typically smaller,mostly coccobacillus,some double arrangement.The results of mannitol and mannose were positive.The results of lactose esculin and sorbic alcohol were negative.2h to 12h was logarithmic phase to APP,12h to 14h the number of bacteria reached the maximum,and after 14h tends to be stable.The results for the detection laid foundation for APP detection,biochemical identification and vaccine production.Conventional drug susceptibility disk diffusion method was used to research the antibiotics sensitivity of isolated APP.The test results show that,APP Anhui isolated strains sensitivity to ciprofloxacin?florfenicol and norfloxacin was the highest,the sensitive rate was 100%;followed by azithromycin and cotrimoxazole,sensitive rate was 85.7%;amikacin.ofloxacin and erythromycin is sensitive,sensitive ratio between 71.4%to 42.9%;to amoxicillin?vancomycin and lincomycin resistance,the sensitive rate was 0.0%.APP Fujian isolated strain sensitivity to ciprofloxacin and ampicillin was the highest,the sensitive rate was 88.9%;followed by norfloxacin?kanamycin and cefazolin,sensitive rate was 77.8%;and penicillin and florfenicol is sensitive,the sensitive rate of between 66.7%to 33.3%,streptomycin,lincolycin resistance and vancomycin sensitive rate was 0.0%.The difference of resistant spectrum in different regions was significant,and this provided guidance for the clinical use of antibiotics.NAD test was used to identify the biotypes of isolated and reference strains APP.The results showed that:APP Anhui isolated and APP reference strains belonged to biotype ?,APP Fujian isolated strain to biotype ?.APal-PFGE was used to identify the genotype of isolated and reference strains APP.The results showed that,APP reference strains and APP strains were divided into 6 genotypes.In different regions and different pig farms the genotypes of isolated APP were different.The study of isolated and referenee strains APP laid the foundation of APP genotype identification and screening dominant strains and vaccine strains.