大肠杆菌耐药株的体外诱导及其acrA和marA基因分析

为检测大肠杆菌在某抗菌素的环境压力下耐药性的变化及其与acrA和marA基因突变的关系.分别用四环素、氯霉素和环丙沙星对大肠杆菌质控株ATCC25922进行体外诱导培养,测定诱导前后多种抗菌药的MIC的变化;对各菌株的acrA和marA基因进行克隆和测定.四环素诱导株产生重耐药,氯霉素和环丙沙星的诱导引起单药耐药;四环素诱导株、氯霉素诱导株和环丙沙星诱导株的acrA和marA基因序列均与ATCC25922的一致.四环素、氯霉素和环丙沙星的诱导培养并未引起ATCC25922的acrA和marA基因突变,诱导引起的大肠杆菌耐药性变化是由于其acrA和marA基因突变以外的其他原因所致.

Induce cultivate and gene analysis of acrA and marA gene in Escherichia coli resistance strain

To inspect the change of drug resistance in Escherichia coli under surroundings pressure caused by some Bacteriophage,and the relationships between the change of drug resistance with acrA and marA gene mutation.The Escherichia coli control strain ATCC25922 was cultured in culture containing inducer with Tetracycline,chloramphenicol,ciprofloxacin,respectively.And the change of MIC was determined before and after induced.At the same time,acrA and marA gene was cloned and sequenced.Tetracycline inducing strains may led to the muti-drug resistance in Escherichia coli,chloramphenicol and ciprofloxacin inducing strains may led to the single-drug resistance.The results of sequencing showed that there were no base change in acrA and marA between inducing strains and ATCC25922.The change of acrA and marA gene hadn't happened in ATCC25922 induced with Tetracycline,chloramphenicol,ciprofloxacin,respecitvely.The change of resistance level of experimental strains was not caused by acrA and marA mutation.