抗生素在体内外对厌氧菌和艰难梭菌细胞毒素生成的作用

Effect of antibiotics on anaerobic bacteria and on cytotxin production by C. difficile In vivo and in vitro

氯林霉素、灭滴灵和甲砜霉素对大多数肠道厌氧菌的生长具抑制作用。氯林霉素还会破坏肠道菌群平衡,使原来受抑制的艰难梭菌得以定植,并在艰难梭菌浓度达10~8/g盲肠内含物时,检测到艰难梭菌细胞毒素。培养基中亚抑菌浓度的氯林霉素和灭滴灵会推迟艰难梭菌细胞霉素的生成。灭滴灵还可保护无菌小鼠及受氯林霉素处理的悉生小鼠免遭艰难梭菌细胞毒素的致死作用,从而证实了灭滴灵在伪膜性结肠炎临床治疗中的可用性。

Most of 95 intestinal anaerobic strains, isolated from human samples, were sensitive to clindamycin, metronidazole and thiamphenicol. The administration of clindamycin in the gnotobiotic mice, in which normally C. diffieile could not colonize, caused intestinal colonization by C. difficile when antibiotic treatment has stopped and when C. difficile was given orally. Moreover, when the population of C.difficile reached 10~8 CFU/g of cecal contents, cytotoxin of C. difficile could be detected in the cecum of the treated animals. Subinhibitory concentrations of clindamycin and metronidazole delayed the appearance of C. difficile cytotoxin in the culture medium. In addition, metronidazole protected germfree mice from the lethal effects of C. difficile toxins and gnotobiotic mice from treatment by clindamycin, confirming the usefullness of metronidazole in the treatment of pseudomembranous colitis.