目的 研究临床分离的8株哑胺培南耐药鲍曼不动杆菌中,与插入序列相关的blaOXA-23mRNA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-234种β-内酰胺酶基因;实时荧光PCR榆测blaOXA-23mRNA表达黾,并以PCR的方法扩增插入序ISAbal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ISAbal,实时荧光PCR检测显示1株菌blaOXA-23mRNA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ISAbal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; blaIMP-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 of ISAbal was main reason that cause blaOXA-23 carbapenemase activity weaken.
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