Isolation, Identification And Detection Of Drug Resistance Genes Of Duck E.Coli Isolates From Gaomi In Shandong Province

Shandong is a big province of poultry in China as an important supply base of poultry and eggs. Avian Escherichia coli disease caused very serious harm to poultry in Shandong province. In recent years, after the intensive culture brought the main diseases under control, Escherichia coli disease shows clear ascendant trend and has become one of main bacterial diseases in the breeding industry.In recent years, the drug resistance rate of bacteria to the antibiotic continues to rise, and the epidemic of multi-drug resistant strains to quinolones, aminoglycosides, and extended-spectrum β-lactam antibiotics has emerged. In Shandong province, the duck industry has developed rapidly. To study of the drug resistance of duck Escherichia coli has important significance for scientific prevention and control of poultry colibacillosis, reduction of drug residues, assurance of food safety and human health. This research consists of three parts:Part one:Fifteen Escherichia coli isolates from diseased ducks in Gaomi of Shandong province during2009to2012were characterized for O serotypes. Four serotypes were identified: O78,O35,O1and O2. O78and O35were the dominant serotypes and occupied80%in all.Part two:Susceptibility test of15strains of duck E. coli strains to10commonly-used clinical antibiotics (levofloxacin, ciprofloxacin, cefoxitin, gentamicin, trimethoprim, cefotaxime, ampicillin, tetracycline, streptomycin) were carried. The result showed that the15E. coli isolates displayed general resistance to commonly used drugs in veterinary clinic. The resistance rate to tetracycline was the highest as93.3%(14/15), followed to ciprofloxacin and erythromycin as86.7%(13/15), and the resistance rate to levofloxacin was the lowest as33.3%(5/15). Part three: By PCR, the resistance genes to aminoglycosides, extended-spectrum β3-lactam, and quinolones were detected in the15duck E. coli strains isolated from Gaomi. The results showed that these strains carried a higher rate of the resistance genes to aminoglycosides, and extended-spectrum β-lactam antibiotics, and the resistance gene to quinolones as qnrA, qnrB and qnrS were not detected.