动物源大肠杆菌PMQR基因流行性检测

【目的】检测分离自广东省散养型养殖场的动物源大肠杆菌中oqxAB基因及其它质粒介导喹诺酮类耐药基因(PMQR)的流行情况。【方法】采用PCR方法检测oqxA、oqxB、qnr、qepA和aac（6′）-Ib-cr基因；琼脂平板稀释法对PMQR阳性菌株进行18种抗菌药物的最小抑菌浓度测定。【结果】qnrB 、qnrS、aac（6′）-Ib-cr、oqxA、oqxB的检出率依次为10.49%、18.88%、31.47%、44.8%和48.9%，但未检测到qnrA、qnrC、qnrD和qepA。oqxA与oqxB的检出率较高，且oqxA与oqxB常常同时存在。多数菌株同时携带两个或两个以上的PMQR基因。PMQR阳性菌对18种兽医临床常用抗生素耐药率较高。【结论】PMQR基因在广东省兽医临床传播广泛，广东省大肠杆菌对临床常用抗菌药物耐药较为严重，药敏谱呈多样化，多重耐药株比例较高。

Detection of PMQR Gene in Escherichia coli Isolated from Animals

【Objective】The objective of the study is to investigate the prevalence of oqxAB gene and other three types of plasmid-mediated quinolone resistance(PMQR) gene in Escherichia coli isolated from free-range farms in Guangdong province.【Method】All the strains were screened for the oqxA,oqxB,qnr,qepA,aac(6′)-Ib-cr genes by PCR.The susceptibility of PMQRpositive strains to 18 antimicrobial agents were determined by agar dilution method.【Results】The positive rates of qnrB,qnrS,aac(6′)-Ib-cr,oqxA,oqxB genes were 10.49%,18.88%,31.47%,44.8%,and 48.9% respectively.No qnrA,qnrC,qnrD and qepA genes were detected in any of the isolates.oqxA and oqxB have a high positive rate,and the two genes always exsist in the same isolates.PMQR gene always shows a coexstence of two or more kinds of the plasmid genes in the same isolates.PMQR positive isolates show a high rate of resistance to 18 antimicrobial agents which was widely used in veterinary clinical medicine.【Conclusion】PMQR gene is very common in veterinary clinic.E.coli isolated from animals in Guangdong province shows a high level resistance to widely used drugs.The antibiotic sensitivity spectrum is variegated.The proportion of multi-drug-resistant strains is high.