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目的了解产AmpC酶肺炎克雷伯菌对氨基糖苷类耐药基因、AmpC型β-内酰胺酶基因,整合子遗传标记的存在状况以及菌株的亲缘关系。方法收集医院住院患者痰液标本中分离的肺炎克雷伯菌20株,头孢西丁三维试验均为阳性,采用聚合酶链反应(PCR)法分析7种氨基糖苷类修饰酶、6种16SrRNA甲基化酶、6种AmpC型β-内酰胺酶基因和3种整合子遗传标记,并对检测结果作样本聚类分析。结果 20株产AmpC酶肺炎克雷伯菌均检出氨基糖苷类耐药基因和blaDHA、intⅠ1基因,氨基糖苷类修饰酶基因检出aac(3)-Ⅱ18株、aac(6’)-Ⅰb 10株、ant(3″)-Ⅰ5株,检出阳性率分别为90.0%、50.0%、25.0%,16SrRNA甲基化酶检出rmtB2株,检出阳性率为85.0%;样本聚类分析提示,该组菌可分为两个簇群,A簇群中又可分为A1、A2两个亚簇群,A1亚簇群中可分为A1.1(1、5、7、8、10、12、16、20号株)和A1.2(6、15)两个子簇群,均为克隆传播;A2亚簇群中可分为A2.1(2、3、4号株)和A2.2(9、11、13、18、19号株)两个子簇群,亦均为克隆传播,B簇群(14、17号株)亦为克隆传播。结论肺炎克雷伯菌耐药表型与基因型结果相符,携带blaDHA基因导致对AmpC型β-内酰胺类药物耐药,携带aac(3)-Ⅱ、aac(6′)-Ⅰb、ant(3″)-Ⅰ、rmtB基因导致对氨基糖苷类药物耐药,Ⅰ类整合子可能是上述基因的载体,本组菌株存在医院感染的可能。
Objective To understand the existence of AmpC β-lactamase gene, integron genetic markers and genetic relationship among strains producing Klebsiella pneumoniae producing AmpC enzyme. Methods Twenty isolates of Klebsiella pneumoniae were collected from the sputum specimens of hospitalized patients. The three-dimensional cefoxitin test was positive. Seven kinds of aminoglycoside-modifying enzymes and six kinds of 16S rRNA were analyzed by polymerase chain reaction (PCR) 6 kinds of AmpC β-lactamase gene and 3 kinds of integron genetic markers, and the test results for sample clustering analysis. Results A total of 20 aminoglycoside resistance genes and blaDHA and intⅠ1 genes were detected in 20 strains of Klebsiella pneumoniae producing AmpC enzyme. AAC (3) - Ⅱ 18 and aac (6 ’) - Ⅰ b 10 genes were detected in aminoglycoside modified enzyme. The positive rate was 90.0%, 50.0% and 25.0%, respectively. The positive rate of rmtB2 was detected by 16S rRNA methylase, and the positive rate was 85.0% The group of bacteria can be divided into two clusters, A cluster can be divided into A1, A2 two sub-clusters, A1 sub-cluster can be divided into A1.1 (1,5,7,8,10, 12, 16 and 20) and A1.2 (6 and 15), all of which are cloned and propagated. A2 subgroups can be divided into A2.1 (strains 2,3 and 4) and A2. 2 (strain 9, 11, 13, 18 and 19) also cloned and the B cluster (strain No. 14 and No. 17) also cloned and transmitted.Conclusion The resistant phenotypes of Klebsiella pneumoniae Consistent with the genotype results, carrying blaDHA gene resulted in resistance to AmpC β-lactams, which led to aac (3) -Ⅱ, aac (6 ’) - Ⅰb, ant Aminoglycoside drug resistance, class Ⅰ integron may be the carrier of these genes, the group of strains of hospital infection may exist.