Surveillance Of Drug Resisitence And Resistance Genes Of Avian Escherichia Coli

Colibacillosis the infectious disease caused by pathogenic Escherichia coli, and spawneda great number of economic loss to chicken husbandry industries. To investigating thedrug resistance and drug resistance gene, so as to provide theoretical for clinical poultrydisease.160bacterial strains were isolated from dead or sick chicken showing typicalsymptoms of E.coli in several regions of Hebei. Determining111were E. coli form160bacterial strains by the test of morphology, biochemical characteristics and PCRtechnique.The resistance test of24antibiotics, such as Azithromycin, Spectinomycin,Erythromycin and the like, were tested according to the K-B method recommended by theThe result were as following,(1) The drug-resistant rate of Streptomycin, Kanamycin,Gentamycin, Neomycin, Amikacin and Spectinomycin were97.30%,96.97%,95.50%,50.45%,45.95%and22.52%for the aminoglycoside antibiotics;(2) The drug-resistant rateof Oxfendanzole, Enrofloxacin, Ciprofloxacin, oxygen, Norfloxacin, Gatifloxacin were99.10%,95.50%,93.69%,91.89%,90.09%and76.58%for the quinolone antibiotics;(3)The drug-resistant rate of Cefazolin, Cefotaxime and Penicillin, Ampicillin-salbactam,Ceftriaxone sodium were100%,100%,100%,94.59%and90.09%for the Lactamantibiotics;(4) The drug-resistant rate of Erythromycin, Tilmicosin, Azithromycin were99.09%,96.40%and57.66%for the macrolides antibiotics;(5) The drug-resistant rate ofLincomycin, Rifampicin, Doxycycline and Fluorine were100.00%,100.00%,90.09%and100.00%. The Statistical of results show that strains avian E.coil isolates in multiple drugresistance with100%from our province, and the drug-resistance is serious.A total of6aminoglycoside resistance genes were checked in111pathogenic E.coliisolates by PCR. There were100（90.09%）E.coli isolates carries aminoglycosideresistance genes. The detection rates of aph(6′)-Id (strB), ant(3′)-Ia（aadA）, aac(3’)-Ⅱ a,aac(6′)-Ib, aph(3′)-Ⅱ a, aph(3′)-Ib(strA)were73.87%，41.44%，31.53%，26.13%，13.51%�'�8.11%. There were11E.coli isolates not carries aminoglycoside resistance genes as wellas did not found all6gene carriers in111pathogenic E.coli isolates. A total of4quinolone resistance plasmid were checked in111pathogenic E.coliisolates by PCR. There were100（90.09%）was amplified resistance plasmid. The positiverates of qnr A, qnrB, qnrS, aac (6’)-Ib-cr were0%（0/111）、0.90%（1/111）、8.11%（9/111）、36.04%（40/111）.Quinolone-resistant determining region(QRDR)of gyrAgeneof40Escherichiacoli were PCR detected, sequenced and the sequence analyzsis.The resultsindicated that the nucleotides were mutated at the sites83and87of QRDR in the40antibiotic-resistant bacterial strains.No mutation was found at the sites72and75of QRDRin theE.colidetected.The mutation of gyrA was important mechanism forantibiotic-resistant E.coli.A total of3β-lactams resistance genes were checked in111pathogenic E.coli isolatesby PCR, The results indicated that the positive rates of Oxa-1, Oxa-3, Oxa-5were0%(0/111),2.7%(3/111) and0.9%(1/111). It is thus clear that the type of Oxa beta lactamasewas not main mechanism for antibiotic-resistant E.coli in the province of hebei.