| Avian colibacillosis caused by avian pathogenic Escherichia coli(APEC)manifested as pericarditis,parahepatitis,peritonitis,septicemia and so on,meningitis are continuously increasing in present.It is a kind of zoonosis,mainly for infants and young animals,and the symptoms are diarrhea and sepsis.Animal husbandry has been an essential part of society.In recent years,with the development of the national economy and the implementation of the preferential policies of the government,there are a large number of broiler farms gradually increasing,and the chicken diseases have become diversified and complicated.One of the more serious is the Chicken Colibacillosis.Through the epidemiological investigation of Escherichia coli from chicken in some areas of Henan Province and the isolation and identification of Escherichia coli,we studied the biochemical characteristics,molecular group,drug resistance and pathogenicity.Probiotics and antibiotics were used to seek the clinical control measures for the prevention of colibacillosis.The results are as follows: 1.Epidemiological investigation of Colibacillosis in broiler chickens in some areas of Henan ProvinceAccording to the criteria of the Chicken Escherichia coli disease of different ages,among the 94 flocks breeded in standardized farms,nine flocks were diagnosed with E.coli disease,accounting for 9.6%;Among the 140 flocks in the shed,after a series of investigations,40 flocks were diagnosed with E.coli disease,accounting for 30.8%.Through the investigation and statistics on the age,morbidity,mortality,mixed infection,secondary infection,chicken farm construction status of 49 broiler flocks that have been determined to be sick,it was found that the incidence rate of standardized chicken farm was 12.7%,the mortality rate was 6.1%;The incidence rate of shed was 47.1% and the mortality rate was 15.5%.The statistical results showed that 8 flocks of all were infected before the age of 14 days,accounting for about 16.3%.35 flocks,at the age of 21-42 days,were infected,accounting for 71.4% of the whole sick flocks.6 infected flocks,at the age of above 45 days,accounted for 9.8% of the total.2.Isolation,identification and drug resistance of Escherichia coli128 strains of Escherichia coli were isolated from the diseased farm.The bacteria were rod-shaped and both ends were blunt.Most strains had flagellum and could move.The size of 2 ~ 3μm × 0.6μm,part of the presence of scattered,part of the existence of pairs.After purification,the colony diameter was 2-3mm,the edge was blunt and round,and the whole was convex.Cultured in the Kang Kai agar plate,colonies will show a black and a certain luster.To determine the genetic origin and molecular characterization,one simple and rapid phylogenetic grouping technique based on triplex PCR which used a comination of chuA and yiaA genes as well as an anonymous DNA fragment TspE4.C2,was adopted to analysis main phylogenetic groups in the APEC isolates.There were groups A(50.78%,65/128),groups B1(11.72%,15/128),groups B2 17.58%,23/128)and groups D(19.92%,25/128)in 128 strains.Drug resistance detection indicated that 4 strains of Escherichia coli were sensitive to 11 antibiotics(2.73%),including ampicillin(AM),streptomycin(STR),compound sulfamethoxazole(SMZ),aztreonam(AZT),ofloxacin(OFLX),norfloxacin(NFLX),Li Fuping(RIFA),kanamycin(KAN),ciprofloxacin(CPFX),gentamicin(GENT),and clindamycin(CLDM),6 strains were only sensitive to AM,while the remaining strains showed multiple drug resistance(92.19%).30 strains of Escherichia coli were resistant to AM,STR and SMZ,accounting for 23.05% of the total.;32 strains of Escherichia coli strains with resistance toAM,STR,SMZ,AZT,OFLX and NFLX 6,accounted for 27.54% of the total,including 29 strains with resistance to AM,CPFX RIFA,NFLX,KAN,OFLX,SMZ,AZT,and STR,accounting for 22.27% of the total.34 strains of Escherichia coli strains were resistant to 11 kinds of antibiotics,accounting for 26.57% of the total.3.The effect of probiotics combined with antibiotics on pathogenic Escherichia coliFor the trial of 24 flocks,with antibiotics alone,the mortality rate was between 12.8%-17.9%,and the cure rate was between 82.1%-87.2%;With probiotics alone,the mortality rate was between 17.7%-37.8%,but the vast majority was between 34.6%-37.8%;With probiotics combined with antibiotics,the mortality rate was between 7.4%-8.8%,and the cure rate was between 90.4%-92.6%.The results showed that the use of drugs or probiotics on E.coli will have a certain therapeutic effect,and the therapy of probiotics combined with antibiotic is the best. |
PDF Full Text Request