大肠埃希菌和肺炎克雷伯菌中ESBLs酶和AmpC酶的检测结果分析

目的:了解对头孢菌素类耐药的大肠埃希菌和肺炎克雷伯菌中ESBLs和AmpC酶的分布及其对抗生素的敏感性。方法:利用双纸片协同试验及纸片法确证试验检测ESBLs,三相试验检测AmpC酶,并用纸片扩散试验和微量稀释法测定细菌对抗生素的敏感性。结果:从头孢噻肟耐药的大肠埃希菌和肺炎克雷伯菌中检出产ESBLs分别为91.4%和96.7%;产AmpC酶分别为17.1%和10.0%;产SSBL分别为8.6%和6.7%。产酶菌株对三代头孢菌素高度耐药,对环丙沙星、庆大霉素及复方新诺明耐药率较高,对亚安培南敏感,产AmpC酶细菌对含酶抑制剂的复合抗生素高度耐药。结论:产生ESBLs和AmpC酶是大肠埃希菌和肺炎克雷伯菌对头孢菌素耐药的重要机制,实验室应对其检测和监测给予足够重视,临床医生也应了解其对抗生素的耐药规律。

Detection of Extended Spectrum β-lactamases and AmpC β-lactamases from Escherichia coli and Klebslella Pneumoniae

Objective To know the distribution and anti-microbial susceptibility of extended spectrum β-Lactamase-and AmpC β-Lactamase-producing Escherichia coli and Klebsiella pneumoniae which are resistant to cephalosporins,Methods AmpC β-Lactamase and extended spectrum β-Lactamases were detected by three-dimensional test,double disk synergy test and disk confirmatory test recommended by National Committee for Clinical Laboratory Standards. Disk diffusion test was used for anti-microbial susceptibility test, the MIC values of AmpC β-lactamase-producing strains were examined by micro-dilutiontest.Results From Escherichia coli and Klebsiella pneumoniae resistant to cefotaxime,extended spectrum β-Lactamase-producers were 91.4%and 96.7%,AmpC β-Lactamase-producers accounted for17.1% and 10.0%,extended spectrum SSBL producers were 8.6% and 6.7%,respectively,These strains were highly resistant to the third-general cephalosporins,but susceptible to impenem.Their resistance ratio to ciprofloxacin, gentamicin and trime thoprim/sulfamethoxazole were higher than that of nonproducers.AmpC β-Lactamase-producers possessed high resistance to antibiotics combined with inhibitors.Conclusion Extended spectrum β-Lactamases and AmpC β-Lactamases are the most important resistance mechanisms of Escherichia coli and Klebsiella pneumoniae to cephalosporins,much attention should be paid to their detection and surveillance.Their resistance to anti -microbial agents should be known by clinicians.