论文部分内容阅读
目的 研究膜孔蛋白OmpF缺失和主动外排在耐药大肠杆菌蓄积亲水性氟喹诺酮环丙沙星、洛美沙星中的作用和意义。方法 菌体内药物蓄积量和主动外排的作用采用荧光测定法 ;细菌膜孔蛋白以SDS PAGE分析。研究的菌株包括大肠杆菌K 12膜孔蛋白缺失突变株JF70 1(OmpF+ )、JF70 3(OmpC+ ) ;敏感株Ecs及其实验室诱变耐药株R2、R2 5 6 ,临床分离耐药株R5、R6。结果 Ecs中的药物蓄积稳态浓度与JF70 1一致 ,较JF70 3高 1/ 5 (环丙沙星 )或 1/ 2 (洛美沙星 ) ,但JF70 3仍对氟喹诺酮敏感 ;而耐药菌中的药物蓄积量除R2稍高于JF70 3外 ,较敏感菌低 2 - 10倍。加入DNP后 ,两个药物的蓄积量均增高 ,尤其耐药株的升高显著 ,表明这些菌株的主动外排 (泵 )系统功能明显增强。膜孔蛋白检查发现 ,Ecs株有OmpF和OmpC ,R2、R2 5 6缺失OmpF ,R5、R6缺失OmpC。结论 大肠杆菌减少对亲水性氟喹诺酮的蓄积量涉及OmpF缺失和主动外排 (泵 ) ,而后者可能是一重要因素。
Objective To study the role and significance of membrane protein OmpF deletion and active efflux in the accumulation of hydrophilic fluoroquinolone ciprofloxacin and lomefloxacin in Escherichia coli. Methods The amount of drug accumulation in the body and the role of active efflux were measured by fluorometry. The bacterial membrane porin was analyzed by SDS PAGE. The strains studied included Escherichia coli K 12 membrane porin deletion mutant JF70 1 (OmpF +), JF70 3 (OmpC +), sensitive strains Ecs and its laboratory mutagenic strains R2, R2 5 6, clinically isolated drug-resistant strains R5 , R6. Results The steady-state concentration of drug in Ecs was consistent with JF70 1, 1/5 (ciprofloxacin) or 1/2 (lomefloxacin) higher than JF70 3, but JF70 3 was still sensitive to fluoroquinolone; In addition to R2 slightly higher than the drug accumulation in JF703, the sensitivity of 2 to 10 times lower. After addition of DNP, the accumulation volume of both drugs increased, especially the resistant strains increased significantly, indicating that the active efflux (pump) system function of these strains was significantly enhanced. Membrane pore examination revealed that Ecs strains had OmpF and OmpC, R2, R250 had OmpF deleted, and R5 and R6 had lost OmpC. Conclusions The reduction of E. coli accumulation of hydrophilic fluoroquinolone involves OmpF deletion and active efflux (pump), which may be an important factor.