Analysis of Drug Resistance and Integron-Gene Cassette Carring in Escherichia coli Isolated from Health Poultry in Jiaodong Region

In order to understand the drug resistance of healthy poultry E.coli and itsⅠandⅡintegron carried and popular features,discuss the correlation of integron and E.coli drug-resistant phenotype,analyze of the role of integron in multiple drug-resistant bacteria,MIC method and polymerase chain reaction(PCR)were used to determine of antimicrobial drug resistance andⅠ,Ⅱintegrase genes and variable area of 249 healthy poultry E.coli respectively,and the enzyme digestion,sequencing analysis of the resistance gene cassettes carried by integron variable area were made.The results showed that the resistant rate of 12 kinds of drugs was more than 56.63%,multiple resistant rate was as high as 98.39%;245multiple drugresistant strains all containedⅠ integron,but only 113 strains E.coli containedⅡ integron,the detection rates ofⅠandⅡintegron were 100%and 46.12%,respectively;63.75% ofⅠ integron positive strains amplified out 5kinds of different size gene cassettes,the size was 1 000-2 300 bp,18.6% ofⅡ integron positive strains amplified out 2 200 bp gene cassette;58.82%of strains carried two or more than two gene cassettes,gene cassettes were priority to encode methoxyl benzyl organism and aminoglycoside drug resistant dfrA and aadA gene families,among them aad A22 as dominant gene cassette,followed by dfrA17 +aadA5gene cassettes.The results indicate that the multiple drug-resistance of poultry E.coli from Jiaodong region is serious;Ⅰintegron is more popular thanⅡ integron,ⅠandⅡintegron both participate in multiple drug resistance,but integron-gene cassette carried by the bacteria has no corresponding relation with its drug-resistant phenotype.