摘要目的 了解临床分离的多药耐药鲍曼不动杆菌(multi-drug resistant Acinetobacter baumannii,MDRAB)β-内酰胺酶基因存在状况以及酶活性.方法 从浙江大学医学院附属第一医院住院患者中分离62株MDRAB,采用PCR及序列分析方法分析22种β-内酰胺酶基因,同时采用酶提取物改良三维试验检测超广谱β-内酰胺酶(ESBLs)、头孢菌素酶(AmpC酶)和金属β-内酰胺酶活性.结果 62株MDRAB中,TEM、OXA-23群和ADC基因阳性株数分别为51株(82.3%)、50株(舳.6%)和36株(58.1%),其余19种基因均为阴性;任选5株TEM基因PCR阳性产物测序比对,显示与GenBank基因库中TEM-1型相同;任选6株OXA-23群基因PCR阳性产物测序比对,显示与OXA-23型碳青霉烯酶基因(登录号:CAB69042.1)相同;任选2株ADC基因测序比对,显示与ADClike型AmpC酶基因(登录号:EU081908)相同.有32株(51.6%)同时产ESBLs和AmpC酶,19株(30.6%)单独产ESBLs,1株(1.6%)单独产AmpC酶;金属β-内酰胺酶活性检测均为阴性.结论 产OXA-23群碳青霉烯酶和ADC型AmpC酶是本组MDRAB对β-内酰胺类药物耐药的主要原因.

abstractsObjective To investigate the distribution of 22 beta-lactamase genes and enzyme activities in multi-drug resistant Acinetobacter baumannii (MDRAB). Methods Sixty-two MDRAB strains were isolated from the First Affiliated Hospital, College of Medicine, Zhejiang University. Twenty-two beta-lactamase genes were analyzed by PCR and verified by DNA sequencing. Enzyme activities of extended spectrum beta-lactamases (ESBLs) , cephalosporinase ( AmpC) and metallo-beta-lactamases ( MBL) were detected by the modified three-dimensional method using enzyme extraction. Results In 62 MDRABs, 51 (82.3% ) , 50 (80.6% ) and 36 (58.1% ) isolates were found to carry blaTEM, blaOXA-23 cluster, and blaADC, respectively. The rest 19 genes were not detected in this study. DNA sequencing and genomic comparison showed that 5 isolates carrying blaTEM had the same genotype as blaTEM-l , 6 isolates carrying blaOXA-23 cluster had the same genotype as blaOXA-23 carbapenemases (accession; CAB69042. 1) , and 2 isolates carrying blaADC had the same genotype as blaADC-like (accession: EU081908). Thirty-two isolates (51.6% ) produced ESBLs and AmpC, 19 isolates (30.6% ) produced ESBLs only, and 1 isolate (1.6%) produced AmpC only; and no isolate produced MBL. Conclusion MDRAB carrying blaOXA-23 carbapenemase and blaADC AmpC in this study are of high drug resistance.