Fig. 3.
Increase in resistance to the 5-nitroimidazole (NI) drugs by the Giardia metronidazole-resistant (MTRR) and C17-resistant (C17R) 106 lines compared with the metronidazole-susceptible (MTRS) parent isolate. ID90 values (concentration of drug at which 10% of control parasite ATP levels are detected) are expressed as μM on a log scale (y-axis) for: the 1-position 5-NIs metronidazole (MTR) and tinidazole (Tz); the 2-position 5-NIs C17 and ronidazole (Rz); the 5-nitrofuran furazolidone (Fur); and the 5-nitrothiazole nitazoxanide (Ntz). For comparison, the minimal inhibitory concentration of 0.39 μM of the benzimidazole albendazole (ALB) for both 106 lines and the parent isolate is included.