摘要
目的 研究环丙沙星及亚胺培南体内诱导铜绿假单胞菌交叉耐药性及交叉耐药机制。方法 以环丙沙星或亚胺培南治疗小鼠铜绿假单胞菌腹膜炎 ,诱导交叉耐药菌 ,分析比较交叉耐药菌与敏感菌的DNA旋转酶 gyrA基因变异、内外膜蛋白差异和细菌对药物摄取的差异。 结果 体内环丙沙星诱导产生环丙沙星耐药菌的交叉耐药率为 3.8% ,环丙沙星对交叉耐药菌最低抑菌浓度(MIC)增加 16～ 6 4倍 ,亚胺培南对交叉耐药菌MIC增加 4～ 16倍 ;体内亚胺培南诱导产生亚胺培南耐药菌的交叉耐药率为 0 .98% ,环丙沙星对交叉耐药菌MIC增加 6 4倍 ,亚胺培南对交叉耐药菌MIC增加 4～ 8倍。体内诱导交叉耐药菌的产生与药物剂量相关。 6株交叉耐药菌 gyrAPCR SSCP(单链构象多态性 )分析发现 ,3株细菌与亲株菌有差异 ;细菌内外膜蛋白分析 ,耐药菌与亲株菌无差异 ;细菌对环丙沙星聚积测定 ,所有交叉耐药菌胞内的药物浓度仅为亲株PA5的 1/ 2～ 1/ 3,加入氰氯苯腙(CCCP)后 ,胞内药物浓度上升至PA5水平或更高。结论 环丙沙星及亚胺培南均可体内诱导铜绿假单胞菌交叉耐药 。
Objective To investigate the mechanism of cross resistant inducibility of ciprofloxacin and imipenem which led to cross resistance in Pseudomonas aeruginosa in vivo. Methods Cross resistant mutant strains were selected and induced with clinical isolates of P.aeruginosa PA5 susceptible to ciprofloxacin and imipenem by experiment of murine peritonitis. Mutation of DNA gyrase gene, drug uptake and membrance proteins of P.aeruginosa PA5 and its mutants resistant to ciprofloxacin and imipenem were examined. Results Both ciprofloxacin and imipenem could induce resistant strain of P.aeruginosa in experimental murine peritonitis, the cross resistance rates after ciprofloxacin and imipenem challenge were 3.8% and 0.98% respectively. The results of PCR SSCP showed that 3 of six cross resistant of P.aeruginosa strains had gyrA gene mutation. Electrophoresis of outer and inner membrane proteins did not exist any difference between cross resistant strains and their parent strain PA5. Fluorometric assay for ciprofloxacin uptake by bacterial cells indicated that the accumulation of ciprofloxacin in all cross resistant variants decreased to 1/2～1/3 compared with that of PA5. After chanllenge with CCCP, the drug uptake in cross resistance mutants increased to the same level as in PA5. Conclusions The results show that cross resistant strains of P. aeruginosa could be selected and induced in vivo. Active drug efflux is the major factor contributing to the cross resistance of P. aeruginosa to both quinolone and imipenem.
出处
《中华传染病杂志》
CAS
CSCD
北大核心
2001年第5期270-274,共5页
Chinese Journal of Infectious Diseases
