国产头孢三嗪对金葡菌,大肠杆菌及绿脓杆菌超微结构影响的观察

本文采用负染和超薄切片技术在电镜下的观察,研究了国产头孢三嗪在高浓度下和亚最低抑菌浓度下对金葡菌、大肠杆菌和绿脓杆菌超微结构的作用。结果显示,10MIC的头孢三嗪作用3小时即可导致细菌发生不可逆性改变,出现细胞膜皱缩,胞质稀疏,细胞膜连续性丧失,甚至细胞破裂,解体死亡。经Sub-MIC的头孢三嗪作用后,金葡菌呈现菌体增大,横膈增宽;而大肠杆菌和绿脓杆菌则表现为菌体增长和菌丝体形成,胞内出现大小不一的空泡,电子密度下降.本研究证实了头孢三嗪为一杀菌类抗生素;提示本药对细菌的形态学改变,主要由于和PBP_3结合所致。

EFFECTS OF HOME-MADE CEFTRIAXONE ON THE ULTRA-STRUCTURAL MORPHOLOGY OF S. AUREUS, E. COLI AND P. AERUGINOSA

The morphlogical and ultra-structural changes of three strains of S. aureus, E, coli and P. aeruginosa were observed under electron microscope after exposure to both high and Sub-inhibitory concentrations of ceftriaxone for three and eighteen hours, respectively. The results showed that the structural changes were almost identical between the bacteria exposing for three hours and the ones for eighteen hours. Shrinking of the cell membrane, rupture of cell wall or even Sysis of the cell were seen when the bacteria were effected by ceftriaxone in the concentration equal to or more 'han 10MIC. When grew with Sub-MIC of ceftriaxone, the S. aureus became larger with irregular shape, decreased dense and a thick cross wall, and the E. coli and P. aeruginosa presented elongation or even filamentation with or without vacuoles in the cell. Our results confirmed previous findings and indicated that ceftriaxone is a bactericidal antibiotic and mainly binds PBP3 of E. coli and P. aeruginosa.