肠出血性大肠埃希菌1类整合子与耐药性关系
Relationship between class 1 integron and resistance in EHEC
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摘要:目的 研究48株(国内28株, 美国20株)肠出血性大肠埃希菌(EHEC)的耐药特点以及1类整合子的分布, 探讨整合子中耐药基因盒的种类及与细菌耐药性的相互关系.方法 琼脂稀释法对18种抗生素进行耐药性监测和分析; PCR法鉴定1类整合子阳性株; PCR产物测序及分析.结果 48株肠出血性大肠埃希菌中23株为O157:H7;2个地域的肠出血性大肠埃希菌对抗生素的耐药情况大多无差别, 只存在对氨苄西林和红霉素耐药率的差异, 前者为国内分离株(607%)高于美国分离株(30%), 后者为美国分离株(95%)高于国内分离株(607%).耐3种以上抗生素的肠出血性大肠埃希菌18株(美国3, 中国15).48株分离株中有11株(229%)鉴定出1类整合子, PCR产物测序分析可见, 9株携带aadA1基因盒, 2株携带aadA2基因盒, 传递对氨基糖苷类抗生素的耐药性.结论 1类整合子及其相关的基因盒广泛存在于肠出血性大肠埃希菌中, 而且决定着对氨基糖苷类抗生素的耐药性.Abstract:Objective To study the distr ibution of class 1 integron in 48 isolates(domestic 28 strains, U.S.A 20 strains) of Entero hemorrhagic E.coli(EHEC), and to explore the sort and relationship of resistance gene cassettes in integrons.Meth ods Routine method was used to isolate EHEC, serotyping; identified virulent strains by PCR; 18 kinds of antibiotics susceptibility were tested using agardilution protocol; class 1 integron was detected also by PCR assay; PCR products were sequenced and analyzed.Results Of 48 EHEC strains 23 were O157:H7.The resistance status was no difference between China and U.S.A isolates except the difference in Ampicillin and Erythromycin, the former that domestic isolates(60.7%)were higherthan those of U.S.A(30%); the latter that U.S.A isolates(95%)were higher than those of China(60.7%).There were 18 isolates(U.S.A 3, China 15)resisted to at least 3 kinds of antibiotics.All EHEC strains resisted to Sulfamethoxazole timetho prim.11(U.S.A 2, China 9)of 48(22.9%)isolates carried class 1integrons; and aadA 1 gene cassette existed in 9 isolates, aa dA 2 gene cassette existed in 2 isolates.And the resistance of aminoglycoside were confered.Conclusion Class 1 integron exists in the EHEC, and determines the resistance of some antibiotics.
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