Investigation And Analysis Of Virulence Factors And Antibiotical Resistance Of Poultry Originated E.coli Strains In Qingdao Region

The E. coli isolated from avian as a conditional pathogenic bacteria not only directly affect the industry production, and its carrying resistance genes and virulence genes can indirectly harm to public health as the food chain. Therefore, this research tested the resistant phenotypes, ESBLs phenotype and genotype, I type and II integron and24kinds of virulence genes as well as analysised the phylogenetic groups of249strains E. coli isolated from apparent health poultry in Shandong Qingdao region from2010to2012,discusses the correlation of resistance、virulence、 phylogenetic groups. Aimed at understanding the popular distribution situation of resistance and virulence genes in E.coli isolated from health poultry in Qingdao region as well as the relationship between the two, providing the basis for effective control of the popularity and spread of such a high poison resistant strains in the production.The PCR method is used in this study for virulence factor investigation and the analysis of phylogenetic groups in E. coli strains. The result shows:the11kinds of virulence factors of24kinds of virulence genes all were detected, virulence factors are widespread and popular in E. coli isolated from health poultry in Qingdao region, and exists in the form of combination and coordinated pathogenic role play, the strains which carried genes combination flmH+iucD+iutA+iroN+iss+VAT+colBM+traT pathogenic is the strongest;The detection rate of high pathogenic group D group and group B2in healthy poultry E. coli strains is higher than other countries; The amount and type of virulence genes, phylogenetic groups in E. coli strains has certain correlation with pathogenic ability strong and the weak, but the virulence strength in E. coli strains and virulence gene number has no corresponding relation.The MIC、ESBLs phenotype screening and confirmation method-. PCR method were adopted in this research for the investigation and analysis in producing ESBLs E. coli from health poultry. Results showed that the resistant in E. coli strains from health poultry in Shandong Qingdao region is severe, the resistant rate of12kinds of drug is more than56.63%, multiple drug resistance problems is prominent, multiple resistant rate is as high as98.39%;. Producing ESBLs strains are popular and spread, the detection rate is as high as83.13%, its drug resistance is relatively serious than producing ESBLs strains; CTX-M (100%) and TEM (99.52%) are the popular genotypes for producing ESBLs strains, and TEM-1、CTX-M-65and CTX-M-55、OXA-1are its advantage gene subtype, and detect the homologous recombination chimeric CTX-M-123and CTX-M-64of CTX-M genotype from healthy poultry for the first time.The PCR method is used in this study for the analysis of integron-gene cassette carring in E. coli strains. Results show that compared with integron Ⅱ type (46.12%), I integron type (100%) is more popular in E. coli strains from poultry in Qingdao region;75.92%of type I integron positive strains amplified out six class gene cassette insert into the area fragments in different size, fragments range is1000～2300bp, among them,1000bp fragment is the highest detection rate,55.91%(104/186);1528bp fragment is the lowest, only1.08%(2/186); only7.96%of the type II integron positive strains amplify the gene cassette segments of2200bp;42.47%%of the Escherichia coli carry two or more than two kinds of gene cassettes, gene cassettes to encode methoxyl benzyl organism and aminoglycoside drug resistant dfrA and aadA gene families is given priority to, including aadA22as dominant gene cassettes,followed by dfrAl2+orfF+aadA2gene cassettes; Ⅰ and Ⅱ integron both participate in multiple drug resistance, but integron-gene cassette carried by the bacteria has no corresponding relation with its drug resistance phenotype.This research used the statistical methods such as SPSS19.0software for the resistance and virulence factor correlation analysis of avian E. coli. The result shows:there were different degree of correlations among the resistant phenotype, integron-gene cassette and virulence genes, phylogenetic groups, the multiple drug-resistant problem of highly pathogenic strains is more prominent; The distribution of different virulence genes in producing ESBLs strains and non-producing ESBLs strains are different, and ESBLs gene subtype and phylogenetic groups also has a certain relevance, such as CTX-M-123and CTX-M-64respectively belong to highly pathogenic group B2group and D group, consistent with the results of previous reports detected homologous recombination chimeric CTX-M-123and the CTX-M-64from the sick animals.