Isolation And Identification Of Chicken Escherichia Coli And Detection Of Tetracycline Resistance Genes Among Escherichia Coli Isolates

The epidemic and spread of E.coli disease caused significant losses to the farmingindustry, E.coli disease mainly caused septicemia, perihepatitis, pericarditis and yolkperitonitis, E. coli can also affect human health by contaminated eggs, egg products and thespread of drug resistance, therefore, to carry out related research on chicken Escherichia colihas important economic and public health significance. In this study,158chicken Escherichiacoli isolated from farms in Shaanxi province,we studied the resistance of four tetracyclinedrugs and resistance genes, and try to explore the correlation between resistance andresistance genes, the research provide theoretical support for mechanism research and diseaseclinical prevention and control.1. Collect liver samples of dead chickens from large-scale chicken farm in Shaanxi bysterile method, inoculated on MacConkey agar and eosin methylene blue agar, pick upsingle colonies, biochemical identification and serotype identification for suspected E.coli,results showed that158strains isolated and identified from450liver samples, and theadvantages serotype is O78and O38.2. With reference to CLSI (clinical and laboratory standards institute), antimicrobialsusceptibility of158chicken E.coli isolates against4antimicrobials were determined by theKirby-Bauer disk method. Results showed that antimicrobial resistance of E.coli totetracycline, chlortetracycline, oxytetracycline and doxycycline are88.6%、77.2%、87.3%、50.6%,separately; Multi-drug resistant strains were up to78.5%.3. According to the E. coli tetracycline resistance gene sequences published in GenBank,3pairs of specific primers were designed by Primer5.0, PCR detection of three kinds oftetracycline resistance genes, and comparison sequences of obtained with related sequences inGenBank by DNAStar software. Results showed that the detection of tetracycline resistancegene tetA, tetB were81.4%and20.7%, no tetC gene were detected;Resistance of chickenPathogenic E.coli to tetracycline antibiotics were common existed, and mainly weremulti-drug-resistance; the detection of resistance gene tetA is significantly associated withtheir antimicrobial resistance (P<0.05).