Gillin F D, Reiner D S
Biochem Pharmacol. 1982 Nov 15;31(22):3694-7. doi: 10.1016/0006-2952(82)90600-1.
The effects of oxygen tension and reducing agents upon the sensitivity of Giardia lamblia to metronidazole in vitro were determined using two different assays. First, the parasites were exposed to drug under high or low oxygen tension in liquid medium with or without fresh cysteine and ascorbic acid. Survival was determined by colony assay. Second, the effect of thiol reducing agents was measured directly by colony assay in semi-solid media (low pO2 conditions). Trophozoites were strikingly (greater than 100-fold) less sensitive to metronidazole under the aerobic condition of the first assay. In contrast, the reducing agents had much lesser effects (2- to 5-fold) depending upon the assay. Finally, G. lamblia isolated from a patient treated with metronidazole unsuccessfully four times showed similar metronidazole sensitivity to a standard strain under both aerobic and reduced O2 tension conditions.
使用两种不同的检测方法，测定了氧张力和还原剂对体外培养的蓝氏贾第鞭毛虫对甲硝唑敏感性的影响。首先，将寄生虫置于含有或不含有新鲜半胱氨酸和抗坏血酸的液体培养基中，在高氧或低氧张力条件下接触药物。通过集落检测法测定存活率。其次，在半固体培养基（低pO2条件）中通过集落检测法直接测量硫醇还原剂的作用。在第一种检测方法的有氧条件下，滋养体对甲硝唑的敏感性显著降低（超过100倍）。相比之下，根据检测方法的不同，还原剂的影响要小得多（2至5倍）。最后，从一名甲硝唑治疗失败4次的患者中分离出的蓝氏贾第鞭毛虫，在有氧和低氧张力条件下，对甲硝唑的敏感性与标准菌株相似。
