抗菌药物诱导性肠球菌耐药的实验讨论*【摘要】 目的 深化讨论肠球菌耐药性的产生机制,指导临床合理用药。方法 采纳一步诱导法,对 8 株粪肠球菌、2 株屎肠球菌和 9 株粪肠球菌、1 株屎肠球菌进行四环素和左氧氟沙星诱导性耐药试验。对诱导出的菌株用琼脂稀释法测定药物敏感性;用 PCR 法检测四环素耐药基因tetM、tetL,用 PCR 法扩增 gyrA、parC 基因后测定 DNA 序列。结果 10 株实验菌中的2 株诱导产生了多株稳定的四环素耐药株。耐药株的 MIC 分别为 16~128μg/ml,与原株比较,增加了 16~512 倍。在 1 株实验菌的诱导耐药株的质粒 DNA 上检测到 tetL 耐药基因,另一株实验菌株的诱导耐药株的染色体 DNA 上检测到 tetM 耐药基因;10 株实验菌中的 2 株诱导产生了多株稳定的左氧氟沙星耐药株。诱导耐药株的 MIC 分别为 16~64μg/ml,与原株比较,增加了 8~32 倍。GyrA 的 QRDR 内的第 87 位或第 83位的氨基酸及 ParC 的 QRDR 内的第 80 位的氨基酸均发生了改变。结论 一步法抗菌药物诱导性耐药试验的结果表明,肠球菌可在高于耐药 MIC 浓度的抗菌药物短期作用后获得耐药性。 【关键词】 肠球菌 抗菌药物 诱导性耐药 抗菌药物压力 Laboratory study of antibacterial agents on enterococcus induced resistance 【Abstract】 Objective The purpose of the present research was to study on the emergence mechanism of enterococcal resistance to a variety of antibacterial agents,and to guide the selection and use of antimicrobial agents in clinical Eight of faecalis enterococcus and two of faecalis enterococcus,nine of faecalis enterococcus and one of faecium enterococcus were selected to performed experiments on induced resistance to tetracycline、levofloxacin respectively by one-step susceptibility of the induced strains resisitant to tetracycline、levofloxacin was measured by determining the MIC using agar dilution method. The tetM and tetL gene in the induced strains were detected by PCR, gyrA and parC gene were amplified by using PCR,then the nucleotide sequence of two g...