Preparation and effect evaluation of the adjuvant vaccine of enteropathogenic Escherichia coli in Tibetan piglets / 中国人兽共患病学报

To study the immune protection of the inactivated vaccine against the enteropathogenic E.coli in Tibetan pigs,the strains isolated from the dead pig was identified by biochemistry and PCR methods.After that,the biological adjuvant vaccine was prepared by following procession.Firstly,selected enteropathogenic E.coli strain was cultured.Then,we harvested the bacteria and inactived it to prepare the antigen.Finally,we added the recombined cholera toxin B subunit as the biological adjuvant,added the mannose in solution 3 ％-5％ (W/V),distributed in ampoule,and freeze-dried.The performances of the vaccine was evaluated by administration for the nine groups of KM mice in oral and intramuscular immuno strategies,respectively.Results demonstrated that the effect of intramuscular injection of low dose containing adjuvant group were better than those without adjuvant group.The oral group contained both high dose of adjuvant group and low dose effect of immune adjuvant group were better than that of high and low dose not containing adjuvant group,and high dose of immune effect was better than low dose immune effect.The antibody titers proved that immunization for 4 times was much better than those immunization for times less than that.The data showed the vaccine was high protection against Tibetan Pig enteropathogenic E.coli challenge,especially the high dose of adjuvant vaccine was 100％ protection rate against enteropathogenic E.coli when orally immunization for 4 times in mice.

The resistant phenotype and resistance gene detection of yak-derived Escherichia coli in Tibet / 中国兽医学报

This study aims to understand the Escherichia coli drug resistance isolated from different parts of Tibet yak in order to provide scientific evidence for controling Escherichia coli.PCR analysis of drug resistance phenotype and drug resistance gene of aminoglycosides,florfenicol and sulfonamides were carried out in 200 strains of yak-derived Escherichia coli from 6 different places in Tibet.The results showed that the resistance rate of aminoglycoside to yak-derived Escherichia coli was 96％ of amikacin,94.59％ of streptomycin,19％ of neomycin,23％ of gentamicin,19％ of kanamycin.The detection rate of rmtB gene was 100％.The drug resistance rate of florfenicol was 25％ with 25％ detection rate of resistance geneflor.The resistance rate of sulfonamides was 32％ with 7％,7％ and 17％ detection rates of sul1,sul2 and sul3 respectively genes,Moreover,the result of drug resistance phenotype was consistent with that of drug resistance gene.Meanwhile,the expression of sull gene in different regions of Tibet were different in drug resistance of the bacilli,and those from the population-intensive and flow-sensitive Lhasa,Nyingchi and Xigaze were more resistant to drug resistance,while those from Ali,Shannan and Nagqu were relatively light.The above-mentioned drug-resistant phenotype and drug resistance genes were detected in different cities and regions of Tibet,and there were multiple drug-resistant phenomena.The results showed that there was resistance to Escherichia coli in Tibetan yak,which should be paid attention to,and suggested that the in Tibetan area the antibiotics should be rationally used to reduce the drug resistance.