摘要
目的 通过3种抗菌药物对大肠埃希菌体外作用,观察细菌的形态变化及释放游离内毒素的水平。方法向细菌量为105CFU/ml肉汤试管中加入抗菌药物,置35°C振荡培养,取1ml用 0.20μm微孔滤器除去膜结合型内毒素（BPLPS）,滤液中含游离内毒素（FLPS）;在BET-32细菌内毒素测定仪上定量检测滤液中FLPS含量;离心肉汤培养物,取沉淀涂片复红染色,光镜下观察菌体形态变化。结果 诱导大肠埃希菌产生FLPS的量依次为头孢他啶、亚胺培南和美罗培南;CTZ低浓度诱导高量FLPS,高浓度诱导低量FLPS产生;不加抗菌药物的对照培养物滤液中也有一定量FLPS;在光学显微镜下观察,CTZ使菌体由小杆状变为大量长丝状,IMP和MEP使菌体保持原有的杆状形态或使菌体呈球杆状。结论3种β-内酰胺类抗菌药物CTZ、IMP和MEP对大肠埃希菌杀菌能力及抗菌活性差异不明显;CTZ、IMP和MEP在杀菌的同时能诱导大肠埃希菌产生大量的FLPS,但诱导强度依次为:CTZ>IMP>MEP;低浓度的CTZ诱导高剂量的FLPS;高浓度的CTZ诱导低剂量的FLPS。
OBJECTIVE To observe the morphology and levels of E.coli released free lipopolysaccharide(FLPS) by in vitro administration of three individual antibiotics. METHODS Antibiotics were added to broth cultures (bacterial concentration 105CFU/ml), then incubation at 35°C with shaking. Samples(1 ml) obtained were filtered through a 0. 2μm pore filter to exclude bound LPS(BPLPS). FLPS is involved in filtrate. FLPS content of filtrates was quantitatively estimated at BET-32 bacteria endotoxin detector. After centrifugation, broth culture precipitates were smeared and stained with fuchsin to observe the morphology change in thallus under optical microscope. RESULTS When E. coli exposed to different antibiotics, the quantities of CTZ-induced FLPS was the most, the next was IMP and the last was MEP. Lower concentration CTZ induced more FLPS and higher concentration induced fewer FLPS. FLPS has been detected in filtrate of growth control (no antibiotic). As examined by optical microscope, CTZ made bacterial morphology change from rod-shape to filamentation. IMP and MEP made thallus keep original rod or sphere-rod shape. CONCLUSIONS There is no significant difference in bactericidal capability and antibacterial activity against E. coli among three β-lactam antibiotics, CTZ, IMP and MEP. While killing a bcterium, CTZ, IMP and MEP can induce E.coli to release large amounts of FLPS. CTZ >IMP>MEP, in inducing intensional order. Lower concentration CTZ induced more FLPS and higher concentration CTZ induced fewer FLPS. IMP and MEP made morphology of E. coli change from rode-shape to sphere-rod, while CTZ made thallus filamented.
出处
《中华医院感染学杂志》
CAS
CSCD
2002年第7期497-500,共4页
Chinese Journal of Nosocomiology
