摘要
目的 研究奇异变形杆菌诱导耐药后外膜通透性改变与其耐药性的关系。方法 用含头孢噻肟的梯度平板多步诱导 2株奇异变形杆菌达稳定耐药 ;以十二烷基硫酸钠 聚丙烯酰胺凝胶电泳法 (SDS PAGE)电泳耐药前后细菌外膜蛋白 ;以高效液相色谱法 (HPLC)测定细菌对环丙沙星的摄取量 ;以扫描、透射电镜观察形态学变化。结果 所诱导的细菌对氟喹诺酮类、头孢类、青霉素类抗生素多重耐药 ;耐药株外膜蛋白相对分子质量 40 0 0 0含量下降 ,370 0 0增加 ;耐药株与敏感株对环丙沙星摄取曲线峰浓度比为 1∶1.74和 1∶1.5 3,耐药株中环丙沙星浓度低于临界耐药浓度 1mg/L ,且耐药株和敏感株胞内浓度相差不到 2倍 ,而其MIC却相差较大 ;电镜下耐药株菌体变短 ,外膜皱褶明显 ,间隙加宽 ,胞内空泡减少。结论 奇异变形杆菌被诱导多重耐药后 ,对药物摄入减少 ,结构发生变化 。
Objective To investigate the alterations of outer membrane permeation of multiple antibiotic resistant Proteus mirabilis. Methods Laboratory derived cefotaxime resistant mutants were induced by serial passages of clinical isolated susceptible Proteus mirabilis on cefotaxime containing agar. Thereafter, the outer membrane proteins(OMP) of the parental strains and mutants were analyzed by sodium dodecyl sulfate polyacrylamide gradient gel electrophresis(SDS PAGE) and the uptake of ciprofloxacin(CPLX) was determined with high pressure liquid chromatography (HPLC). Lastly, morphological analysis was performed by scanning and transmission electron microscopy. Results Compared with the parental strains, the mutants were resistant to quinolones, cephalosporins and penicillins; the content of OMP with relative molecular weight 40 000 was reduced and that of 37 000 OMP was increased. The uptake of CPLX was reduced and the ratios of peak concentration were decreased to 1∶1.74, 1∶1.53 compared with that of susceptible strains. CPLX concentration absorbed was lower than the break point 1 mg/L of resistance and the difference of CPLX intracellular concentration between resistant and susceptible strains was less than 2 times, which resulted in much more increase of minimum inhibitory concentrations(MICs). Meanwhile, it was observed under electronic microscopy that resistant strains lost the rodlike shape and had more distinctive membrane fold, wider periplasmic space and less nucleiods. Conclusion The multiple antibiotic resistant Proteus mirabilis shows decrease of drug uptake and changes of ultrastructure, which may be related to alterations of outer membrane permeation.
出处
《中华传染病杂志》
CAS
CSCD
北大核心
2000年第3期155-158,共4页
Chinese Journal of Infectious Diseases
关键词
奇异变形杆菌
外膜蛋白
通透性
抗药性
Proteus mirabilis
Outer membrane protein
Drug resistance
Drug uptake
Ultrastructure
