Evaluation of the in vitro effect of albendazole, metronidazole and nitazoxanide on viability and structure of Giardia lamblia cysts.

Effect of albendazole, metronidazole and nitazoxanide on the viability and structure of Giardia lamblia cysts isolates from infected children. The viability was evaluated by inducing excystation in a low-pH solution followed by an incubation in TYI-S culture medium. Nitazoxanide exhibited potent inhibitory effect (100%), metronidazole (79%) and albendazole (31%). The analysis among groups indicated a rs = 0.75 and p < 0.05. By TEM the cysts incubated with albendazole did not show morphological changes; with metronidazole, the formation of residual bodies in the nucleus border was observed. Incubated with nitazoxanide the damage to the cyst wall was evident, with the formation of areas with a granular content and the presence of cytoplasmic components in the peritrophic space. Our results propose that nitazoxanide showed a high effect on the viability and structure of G. lamblia cysts.