持续高产AmpC酶的检测及其临床意义  

Detection of continuous hyperproduced AmpC enzyme and its clinical significance

作　　者：姚玉华[1] 史伟峰[1] 王玉月[1] 赵艳[1] 

机构地区：[1]江苏省常州市第一人民医院检验科,213003

出　　处：《国外医学（临床生物化学与检验学分册）》2005年第9期581-583,586,共4页Foreign Medical Sciences(section of Clinical Biochemistry and Laboratory Medicine

摘　　要：目的调查持续高产AmpC酶在大肠埃希菌、肺炎克雷伯菌和鲍曼不动杆菌中的携带率和流行趋势。方法用头孢西丁药敏纸片法(K-B法)和头孢西丁三维试验作AmpC酶的筛选、确证试验,对AmpC酶阳性者进行质粒接合试验。结果11种抗生素中亚胺培南的抗菌活性最强,耐药率仅为1.1%。头孢西丁纸片筛选法阳性率为84.4%,三维试验阳性率为32.2%。与三维试验相比,纸片筛选法总的假阳性率为54.4%,两种方法差异具有高度显著性(P<0.001)。AmpC酶、超广谱β-内酰胺酶(ESBLs)、AmpC酶+ESBLs阳性率分别为24.4%、54.4%和7.8%,其中以肺炎克雷伯菌AmpC酶阳性率最高,达33.3%。大肠埃希菌ESBLs阳性率最高,达70.0%。29株AmpC酶阳性菌中,5株耐药质粒转移成功。结论AmpC酶可由染色体或质粒介导,但以染色体介导为主。头孢西丁三维试验可准确检出持续高产AmpC酶,对指导临床用药有积极意义。Objective To investigate the schlepping rates and prevalence trend of continuous hyperproduced AmpC enzyme expressed constitutively at high level in Escherichia coli, Klebsiella pneumoniae and Acinetobacter baumannii. Methods AmpC enzyme was screened by cefoxitin susceptibility disk test（K-B method）and confirmed by cefoxitin three-dimensional test. The strains with AmpC enzyme positive were performed by plasmid conjugation test. Results Imipenem possessed high antimicrobial activity and its resistant rate was 1.1%. The positive rate of cefoxitin screening test and three-dimensional test was 84.4%, 32.2%, respectively. Compared with three-dimensional test, the total false positive rate of cefoxitin screening test was 54.4% .and there was highly significant difference between the two methods（P〈0.001）. The positive rates of AmpC, ESBLs and AmpC plus ESBLs were 24.4% ,54.4 % and 7.8%, respectively. 33.3% of Klebsiella pneumoniae produced AmpC enzyme, and the rate of ESBLs in Escherichia coli was 70.0%. Among 29 strains with AmpC enzyme positive, 5 strains of resistant plasmids were successfully transferred. Conclusion AmpC enzyme can be mediated by chrosome or plasmid,but largely mediated by chrosome. Cefoxifin three-dimensional test can accurately detect continuous hyperproduced AmpC enzyme and have active significance for antimicrobial application in clinic.

关 键 词：三维试验 AMPC酶 头孢西丁 持续高产AMPC酶 临床意义 超广谱Β-内酰胺酶 肺炎克雷伯菌 纸片筛选法 三维试验 大肠埃希菌 染色体介导 头孢西丁 

分 类 号：R446.5[医药卫生—诊断学]