64株鸭致病性大肠杆菌氨基糖苷类药物耐药表型及aaC2耐药基因的调查

Investigation on Resistance Phenotype and Resistance Gene aaC2 against Aminoglycoside Antibiotics in 64 Strains of Pathogenic E.coli from Ducks

为调查鸭源致病性大肠杆菌氨基糖苷类药物aaC2耐药基因的携带情况,探讨aaC2基因与氨基糖苷类抗生素耐药表型的相关性,对64株鸭源致病性大肠杆菌采用了K-B法,选用氨基糖苷类药物链霉素、新霉素、庆大霉素、阿米卡星、观壮霉素和卡那霉素进行了药敏试验,同时用PCR技术对鸭源致病性大肠杆菌aaC2基因进行检测,并对药敏试验结果和aaC2耐药基因检测结果进行比较分析。结果显示,在6种药物中大肠杆菌对链霉素的耐药率最高为60%,对庆大霉素的耐药率为34.5%,对阿米卡星的耐药率为4.2%;64株鸭源致病性大肠杆菌耐药基因aacC2的检出率为25%,获得的基因片段与预期大小一致,长度为384bp,序列分析表明,3株鸭源致病性大肠杆菌扩增的产物与GenBank中的相应的序列有很高的同源性(达99.7%)。药敏试验耐药性和分子水平检测耐药基因的结果比较发现,aaC2基因对大肠杆菌的链霉素,卡那霉素的耐药性有重大的影响,而对阿米卡星耐药性无影响。

In order to investigate the existence of anti-aminoglycoside antibiotics aaC2 gene in pathogenic E.coli from ducks and to study its relationship with the resistance phenotype,the aminoglycoside antibiotics including streptomycin,neomycin,gentamycin,kanamycin,amikacin and spectinomycin were selected to conducted the drug sensitivity tests for 64 strains of E.coli from ducks by using the K-B method,and the aaC2 genes in these bacteria were detected by PCR,then the results of drug sensitivity test were compared with that of aaC2 gene detection.The results show that,of 6 kinds of drugs,the resistance rates of E.coli to streptomycin,gentamycin and amikacin are 60%,34.5% and 4.2% respectively.The positive rate of aaC2 gene in 64 strains of isolates is 25%,the gene fragments with length of 384 bp are amplified which is uniform with the expectation,and the analysis of the sequences shows that the amplified products from 3 strains of E.coli show the homology high up to 99.7% with the corresponding sequences in GenBank.Comparison of the drug resistance results with that of resistance gene detection demonstrates that,aaC2 gene has significant influence on the resistance of E.coli to streptomycin and kanamycin,but no influence on amikacin.