耐亚胺培南鲍曼不动杆菌的碳青霉烯酶基因型研究

Study on the carbapenemases genotypes of imipenem-resistant Acinetobacter baumannii strains

目的研究重庆地区对亚胺培南耐药的鲍曼不动杆菌(CRAb)的耐药性及碳青霉烯酶基因型。方法收集2007年1月至2009年12月重庆地区某两所教学医院153株从患者分离的对亚胺培南耐药的CRAb,用琼脂稀释法测定14种抗菌药物的最小抑菌浓度,PCR扩增D类碳青霉烯酶基因blaOXA-23-like、blaOXA-24-like、blaOXA-51-like、blaOXA-58-like。用EDTA纸片法检测金属酶表型,PCR检测基因型blaI MP、blaVI M、blaSI M。结果所有耐碳青霉烯类的CRAb除对阿米卡星、庆大霉素和左氧氟沙星等保持一定敏感性外,对其余抗菌药物耐药率均为100%。所有耐碳青霉烯类的CRAb均产OXA-23型碳青霉烯酶,在blaOXA-23-like上游连接有ISAba1启动元件。结论重庆地区流行的对亚胺培南耐药的CRAb均产OXA-23型碳青霉烯酶。

Objective To identify the antibiotic resistance,and the carbapenemases genotypes of imipenem-resistant strains of Acinetobacter baumannii isolated from Chongqing.Methods Collected 153 strains of imipenem-resistant Acinetobacter baumannii from 2 teaching hospitals in Chongqing.Broth dilution method detected patterns of resistant against 14 antimircobial agents,PCR was performed to detected class D β-lactamase encoding genes.Detected phenotype of Metallo β-lactamase by EDTA disk method,PCR amplified blaIMP,blaVIM,blaSIM.Results All strains kept low susceptibility to amikacin,gentamicin and levofloxacin,but resistance to other agents.All strains produced carbapenemases which were confirmed as OXA-23 by PCR,a promoter ISAba1 was found in the upstream of OXA-23.Metallo β-lactamase was negative in any of the isolates.Conclusion OXA-23 gene is the most popular carbapenemases coding genes in imipenem-resistant Acinetobacter baumannii in Chongqing.