亚胺培南耐药鲍曼不动杆菌由插入序列ISAba1点突变引起的bla_(OXA-23)表达减低  

Study on lower expression of bla_(OXA-23) associated with point mutation of insertion sequence ISAba1 in imipenem-resistance Acinetobacer baumannii

作　　者：武大伟[1] 魏殿军[1] 马全玲[1] 门昆[1] 曹阳[1] 

机构地区：[1]天津医科大学第二医院检验科,天津300211

出　　处：《中国抗生素杂志》2011年第5期398-400,I0001,I0002,共5页Chinese Journal of Antibiotics

基　　金：天津市卫生局科技基金资助项目(06KZ31);天津市高等学校科技发展基金计划项目(20060620)

摘　　要：目的研究临床分离的8株亚胺培南耐药鲍曼不动杆菌中,与插入序列相关的blaOXA-23 mRNA的表达情况。方法应用双纸片增效法进行金属酶表型筛查并以PCR的方法扩增blaIMP-1、blaIMP-2、blaVIM-2和blaOXA-23 4种β-内酰胺酶基因;实时荧光PCR检测blaOXA-23 mRNA表达量,并以PCR的方法扩增插入序列ISAba1并测序。结果 4株菌金属酶表型筛查为阳性结果,PCR检测8株菌blaOXA-23阳性,2株blaIMP-1阳性、3株blaIMP-2阳性、blaVIM-2基因均为阴性;所有菌株均存在插入序列ISAba1,实时荧光PCR检测显示1株菌blaOXA-23 mRNA表达升高,其余7株菌与对照株比较为表达减低或相近,且这7株菌的插入序列存在点突变现象。结论插入序列ISAba1点突变是引起blaOXA-23碳青霉稀酶活性减低的主要原因。Objective To investigate the expression ofblaOXA-23 mRNA in imipenem-resistance strains. Methods MBLs were checked by imipenem/imipenem-EDTA combination test; bla-IMP-1, blaiMP-2, blaVIM-2 and blaOXA-23 encoding genes were detected by PCR; blaOXA-23 mRNA expression was detected by real-time RT RCR, insertion gene ISAbal was amplified by PCR, then was sequenced. Results 4 strains showed MBLs positive; 8 strains blaOXA-23 positive, 2 strains blaIMP-1 positive, 3 strains blaiMP_2 positive, blaviM_2 genes were negative; 1 strain indicated higher expression of blaOXA-23 mRNA, other 7 strains were lower expression compared to control strain and point mutation of ISABal happened to these strains. Conclusion point mutation oflSAbal was main reason that cause blaOXA-23 carbapenemase activiW weaken.

关 键 词：鲍曼小动杆菌 blaOXA-23mRNA 插入序列ISAbal 

分 类 号：Q78[生物学—分子生物学]